#include <cassert>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <functional>
#include <iostream>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;

using Int = long long;

template <class T1, class T2> ostream &operator<<(ostream &os, const pair<T1, T2> &a) { return os << "(" << a.first << ", " << a.second << ")"; };
template <class T> ostream &operator<<(ostream &os, const vector<T> &as) { const int sz = as.size(); os << "["; for (int i = 0; i < sz; ++i) { if (i >= 256) { os << ", ..."; break; } if (i > 0) { os << ", "; } os << as[i]; } return os << "]"; }
template <class T> void pv(T a, T b) { for (T i = a; i != b; ++i) cerr << *i << " "; cerr << endl; }
template <class T> bool chmin(T &t, const T &f) { if (t > f) { t = f; return true; } return false; }
template <class T> bool chmax(T &t, const T &f) { if (t < f) { t = f; return true; } return false; }
#define COLOR(s) ("\x1b[" s "m")


// T: monoid representing information of an interval.
//   T()  should return the identity.
//   T(S s)  should represent a single element of the array.
//   T::pull(const T &l, const T &r)  should pull two intervals.
template <class T> struct SegmentTreePoint {
  int logN, n;
  vector<T> ts;
  SegmentTreePoint() : logN(0), n(0) {}
  explicit SegmentTreePoint(int n_) {
    for (logN = 0, n = 1; n < n_; ++logN, n <<= 1) {}
    ts.resize(n << 1);
  }
  template <class S> explicit SegmentTreePoint(const vector<S> &ss) {
    const int n_ = ss.size();
    for (logN = 0, n = 1; n < n_; ++logN, n <<= 1) {}
    ts.resize(n << 1);
    for (int i = 0; i < n_; ++i) at(i) = T(ss[i]);
    build();
  }
  T &at(int i) {
    return ts[n + i];
  }
  void build() {
    for (int u = n; --u; ) pull(u);
  }

  inline void pull(int u) {
    ts[u].pull(ts[u << 1], ts[u << 1 | 1]);
  }

  // Changes the value of point a to s.
  template <class S> void change(int a, const S &s) {
    assert(0 <= a); assert(a < n);
    ts[a += n] = T(s);
    for (; a >>= 1; ) pull(a);
  }

  // Applies T::f(args...) to point a.
  template <class F, class... Args>
  void ch(int a, F f, Args &&... args) {
    assert(0 <= a); assert(a < n);
    (ts[a += n].*f)(args...);
    for (; a >>= 1; ) pull(a);
  }

  // Calculates the product for [a, b).
  T get(int a, int b) {
    assert(0 <= a); assert(a <= b); assert(b <= n);
    if (a == b) return T();
    a += n; b += n;
    T prodL, prodR, t;
    for (int aa = a, bb = b; aa < bb; aa >>= 1, bb >>= 1) {
      if (aa & 1) { t.pull(prodL, ts[aa++]); prodL = t; }
      if (bb & 1) { t.pull(ts[--bb], prodR); prodR = t; }
    }
    t.pull(prodL, prodR);
    return t;
  }

  // Calculates T::f(args...) of a monoid type for [a, b).
  //   op(-, -)  should calculate the product.
  //   e()  should return the identity.
  template <class Op, class E, class F, class... Args>
#if __cplusplus >= 201402L
  auto
#else
  decltype((std::declval<T>().*F())())
#endif
  get(int a, int b, Op op, E e, F f, Args &&... args) {
    assert(0 <= a); assert(a <= b); assert(b <= n);
    if (a == b) return e();
    a += n; b += n;
    auto prodL = e(), prodR = e();
    for (int aa = a, bb = b; aa < bb; aa >>= 1, bb >>= 1) {
      if (aa & 1) prodL = op(prodL, (ts[aa++].*f)(args...));
      if (bb & 1) prodR = op((ts[--bb].*f)(args...), prodR);
    }
    return op(prodL, prodR);
  }

  // Find min b s.t. T::f(args...) returns true,
  // when called for the partition of [a, b) from left to right.
  //   Returns n + 1 if there is no such b.
  template <class F, class... Args>
  int findRight(int a, F f, Args &&... args) {
    assert(0 <= a); assert(a <= n);
    if ((T().*f)(args...)) return a;
    if (a == n) return n + 1;
    a += n;
    for (; ; a >>= 1) if (a & 1) {
      if ((ts[a].*f)(args...)) {
        for (; a < n; ) {
          if (!(ts[a <<= 1].*f)(args...)) ++a;
        }
        return a - n + 1;
      }
      ++a;
      if (!(a & (a - 1))) return n + 1;
    }
  }

  // Find max a s.t. T::f(args...) returns true,
  // when called for the partition of [a, b) from right to left.
  //   Returns -1 if there is no such a.
  template <class F, class... Args>
  int findLeft(int b, F f, Args &&... args) {
    assert(0 <= b); assert(b <= n);
    if ((T().*f)(args...)) return b;
    if (b == 0) return -1;
    b += n;
    for (; ; b >>= 1) if ((b & 1) || b == 2) {
      if ((ts[b - 1].*f)(args...)) {
        for (; b <= n; ) {
          if (!(ts[(b <<= 1) - 1].*f)(args...)) --b;
        }
        return b - n - 1;
      }
      --b;
      if (!(b & (b - 1))) return -1;
    }
  }
};

////////////////////////////////////////////////////////////////////////////////


constexpr Int INF = 1001001001001001001LL;

struct NodeMin {
  Int mn;
  NodeMin() : mn(+INF) {}
  NodeMin(Int val) : mn(val) {}
  void pull(const NodeMin &l, const NodeMin &r) {
    mn = min(l.mn, r.mn);
  }
  void ch(Int val) {
    mn = val;
  }
  void chmin(Int val) {
    if (mn > val) mn = val;
  }
  bool test(Int tar) const {
    return (mn <= tar);
  }
};
struct NodeMax {
  Int mx;
  NodeMax() : mx(-INF) {}
  NodeMax(Int val) : mx(val) {}
  void pull(const NodeMax &l, const NodeMax &r) {
    mx = max(l.mx, r.mx);
  }
  void ch(Int val) {
    mx = val;
  }
  void chmax(Int val) {
    if (mx < val) mx = val;
  }
  bool test(Int tar) const {
    return (mx >= tar);
  }
};

////////////////////////////////////////////////////////////////////////////////


int N, L;
vector<int> P;


namespace brute {
Int dp[210][260][260];
Int run() {
  const int lim = max(*max_element(P.begin(), P.end()) - L, 0);
  for (int i = 0; i <= N; ++i) {
    for (int x = 0; x <= lim; ++x) for (int y = 0; y <= lim; ++y) {
      dp[i][x][y] = INF;
    }
  }
  dp[0][0][0] = 0;
  for (int i = 0; i < N; ++i) {
    vector<pair<int, int>> es(lim + 1);
    for (int x = 0; x <= lim; ++x) {
      if (x < P[i] - L) {
        es[x] = make_pair((P[i] - L) - x, P[i] - L);
      } else if (P[i] < x) {
        es[x] = make_pair(x - P[i], P[i]);
      } else {
        es[x] = make_pair(0, x);
      }
    }
    for (int x = 0; x <= lim; ++x) for (int y = 0; y <= lim; ++y) {
      chmin(dp[i + 1][es[x].second][y], dp[i][x][y] + es[x].first);
      chmin(dp[i + 1][x][es[y].second], dp[i][x][y] + es[y].first);
    }
  }
  Int ans = INF;
  for (int x = 0; x <= lim; ++x) for (int y = 0; y <= lim; ++y) {
    chmin(ans, dp[N][x][y]);
  }
  return ans;
}
}  // brute


namespace fast {
struct Node {
  int l, r;
  Int mn[3], lz;
  Node() : l(0), r(0), mn{INF, INF, INF}, lz(0) {}
  void add(Int val) {
    for (int k = 0; k < 3; ++k) mn[k] += val;
    lz += val;
  }
};
int V;
Node nodes[20'000'010];

void push(int u) {
  const int l = nodes[u].l;
  const int r = nodes[u].r;
  Int &lz = nodes[u].lz;
  if (lz) {
    if (l) nodes[l].add(lz);
    if (r) nodes[r].add(lz);
    lz = 0;
  }
}
void pull(int u) {
  const int l = nodes[u].l;
  const int r = nodes[u].r;
  for (int k = 0; k < 3; ++k) nodes[u].mn[k] = min(nodes[l].mn[k], nodes[r].mn[k]);
}

void init() {
  V = 1;
}
void rangeAdd(int u, Int val) {
  nodes[u].add(val);
}
Int rangeMin(int u, int L, int R, int a, int b, int k) {
  if (b <= L || R <= a) return INF;
  if (a <= L && R <= b) return nodes[u].mn[k];
  push(u);
  const int Mid = (L + R) >> 1;
  const Int resL = rangeMin(nodes[u].l, L, Mid, a, b, k);
  const Int resR = rangeMin(nodes[u].r, Mid, R, a, b, k);
  pull(u);
  return min(resL, resR);
}
int merge(int u, int v) {
  if (!u) return v;
  if (!v) return u;
  if (!nodes[u].l && !nodes[u].r && !nodes[v].l && !nodes[v].r) {
    for (int k = 0; k < 3; ++k) chmin(nodes[u].mn[k], nodes[v].mn[k]);
    return u;
  }
  push(u);
  push(v);
  nodes[u].l = merge(nodes[u].l, nodes[v].l);
  nodes[u].r = merge(nodes[u].r, nodes[v].r);
  pull(u);
  return u;
}
int pointChmin(int u, int L, int R, int a, const Int *val) {
  if (!u) {
    u = V++;
    nodes[u] = Node();
  }
  if (L + 1 == R) {
    for (int k = 0; k < 3; ++k) chmin(nodes[u].mn[k], val[k]);
    return u;
  }
  push(u);
  const int Mid = (L + R) >> 1;
  if (a < Mid) {
    nodes[u].l = pointChmin(nodes[u].l, L, Mid, a, val);
  } else {
    nodes[u].r = pointChmin(nodes[u].r, Mid, R, a, val);
  }
  pull(u);
  return u;
}
void dfs(int u, int L, int R) {
  if (L + 1 == R) {
    if (nodes[u].mn[0] < INF || nodes[u].mn[1] < INF || nodes[u].mn[2] < INF) {
      cerr << L << ":" << nodes[u].mn[0] << "," << nodes[u].mn[1] << "," << nodes[u].mn[2] << " ";
    }
    return;
  }
  push(u);
  const int Mid = (L + R) >> 1;
  dfs(nodes[u].l, L, Mid);
  dfs(nodes[u].r, Mid, R);
}

int dp[50010][2];
int xsLen;
vector<int> xs;

Int rangeMin(int u, int a, int b, int k) {
  return rangeMin(u, 0, xsLen, a, b, k);
}
void update(int i, int j, int x, Int c) {
// cerr<<COLOR("93")<<"update i="<<i<<" j="<<j<<" x="<<x<<" c="<<c<<COLOR()<<endl;
  const int l = lower_bound(xs.begin(), xs.end(), x) - xs.begin();
  const Int val[3] = {c - x, c, c + x};
  dp[i][j] = pointChmin(dp[i][j], 0, xsLen, l, val);
}

Int run() {
  vector<pair<int, int>> pis(N);
  for (int i = 0; i < N; ++i) {
    pis[i] = make_pair(P[i], i);
  }
  sort(pis.begin(), pis.end());
  SegmentTreePoint<NodeMin> seg(N);
  for (int h = 0; h < N; ++h) {
    seg.at(h) = pis[h].second;
  }
  seg.build();
  
  // not included in [x, x + L]
  auto getNext = [&](int x) -> int {
    const int posL = lower_bound(pis.begin(), pis.end(), make_pair(x, -1)) - pis.begin();
    const int posR = lower_bound(pis.begin(), pis.end(), make_pair(x + L + 1, -1)) - pis.begin();
    Int mn = N;
    chmin(mn, seg.get(0, posL).mn);
    chmin(mn, seg.get(posR, N).mn);
    return (int)mn;
  };
  // not included in [x0, x0 + L] \cup [x1, x1 + L]
  auto getNext2 = [&](int x0, int x1) -> int {
    const int pos0L = lower_bound(pis.begin(), pis.end(), make_pair(x0, -1)) - pis.begin();
    const int pos0R = lower_bound(pis.begin(), pis.end(), make_pair(x0 + L + 1, -1)) - pis.begin();
    const int pos1L = lower_bound(pis.begin(), pis.end(), make_pair(x1, -1)) - pis.begin();
    const int pos1R = lower_bound(pis.begin(), pis.end(), make_pair(x1 + L + 1, -1)) - pis.begin();
    Int mn = N;
    chmin(mn, seg.get(0, pos0L).mn);
    if (pos0R < pos1L) {
      chmin(mn, seg.get(pos0R, pos1L).mn);
    }
    chmin(mn, seg.get(pos1R, N).mn);
    return (int)mn;
  };
  
  xs.resize((N << 1) + 1);
  for (int i = 0; i < N; ++i) {
    xs[i << 1    ] = P[i] - L;
    xs[i << 1 | 1] = P[i];
  }
  xs[N << 1] = 0;
  sort(xs.begin(), xs.end());
  xs.erase(unique(xs.begin(), xs.end()), xs.end());
  xsLen = xs.size();
// cerr<<"xs = "<<xs<<endl;
  
  init();
  // dp[i][j]: previous hand at (i, j), segtree for another hand
  memset(dp, 0, sizeof(dp));
  Int ans = INF;
  {
    const int i = getNext(0);
    if (i == N) {
      chmin(ans, 0LL);
    } else {
      assert(0 < P[i] - L);
      update(i, 0, 0, P[i] - L);
    }
  }
  for (int i = 0; i < N; ++i) {
    {
      const int h = lower_bound(pis.begin(), pis.end(), make_pair(P[i], i)) - pis.begin();
      seg.change(h, N);
    }
    for (int j = 0; j < 2; ++j) {
      const int x = P[i] + L * (j - 1);
      const int ii = getNext(x);
// cerr<<"i = "<<i<<", j = "<<j<<", x = "<<x<<", ii = "<<ii<<endl;
// cerr<<"  dp["<<i<<"]["<<j<<"] = "<<dp[i][j]<<": ";dfs(dp[i][j],0,xsLen);cerr<<endl;
      if (ii == N) {
        const Int res = rangeMin(dp[i][j], 0, xsLen, 1);
// cerr<<"  "<<__LINE__<<" chmin(ans, "<<res<<")"<<endl;
        chmin(ans, res);
      } else {
        // move another hand to cover ii
        const int posL = lower_bound(xs.begin(), xs.end(), P[ii] - L) - xs.begin();
        const int posR = upper_bound(xs.begin(), xs.end(), P[ii]) - xs.begin();
// cerr<<"  posL = "<<posL<<", posR = "<<posR<<endl;
        {
          const Int res = rangeMin(dp[i][j], 0, posL, 0);
          if (res < INF) {
            update(ii, 0, x, res + (P[ii] - L));
          }
        }
        for (int l = posL; l < posR; ++l) {
          const Int res = rangeMin(dp[i][j], l, l + 1, 1);
          if (res < INF) {
            Int x0 = x, x1 = xs[l];
            if (x0 > x1) {
              swap(x0, x1);
            }
            const int iii = getNext2(x0, x1);
// cerr<<"    l = "<<l<<", res = "<<res<<", iii = "<<iii<<endl;
            if (iii == N) {
              chmin(ans, res);
// cerr<<"  "<<__LINE__<<" chmin(ans, "<<res<<")"<<endl;
            } else {
              // cover iii
              if (P[iii] < x0) {
                update(iii, 1, x1, res + (x0 - P[iii]));
              } else if (x0 < P[iii] - L && P[iii] < x1) {
                update(iii, 0, x1, res + ((P[iii] - L) - x0));
                update(iii, 1, x0, res + (x1 - P[iii]));
              } else if (x1 < P[iii] - L) {
                update(iii, 0, x0, res + ((P[iii] - L) - x1));
              } else {
                assert(false);
              }
            }
          }
        }
        {
          const Int res = rangeMin(dp[i][j], posR, xsLen, 2);
          if (res < INF) {
            update(ii, 1, x, res - P[ii]);
          }
        }
        // move previous hand to cover ii
        if (P[ii] < x) {
          rangeAdd(dp[i][j], x - P[ii]);
          dp[ii][1] = merge(dp[ii][1], dp[i][j]);
        } else if (x < P[ii] - L) {
          rangeAdd(dp[i][j], (P[ii] - L) - x);
          dp[ii][0] = merge(dp[ii][0], dp[i][j]);
        } else {
          assert(false);
        }
      }
    }
  }
cerr<<"V = "<<V<<endl;
  return ans;
}
}  // fast


int main() {
  for (; ~scanf("%d%d", &N, &L); ) {
    P.resize(N);
    for (int i = 0; i < N; ++i) {
      scanf("%d", &P[i]);
    }
cerr<<"N = "<<N<<", L = "<<L<<endl;
// cerr<<"P = "<<P<<endl;
    
    const Int ans = fast::run();
    printf("%lld\n", ans);
#ifdef LOCAL
if(N<=200&&*max_element(P.begin(),P.end())<=200){
 const Int brt=brute::run();
 if(brt!=ans)cerr<<N<<" "<<L<<" "<<P<<": "<<brt<<" "<<ans<<endl;
 assert(brt==ans);
}
cerr<<string(80,'=')<<endl;
#endif
  }
  return 0;
}