#include <bits/stdc++.h>

using namespace std;

#ifdef LOCAL
template <class... T> void dbg(T... x) { char e{}; ((cerr << e << x, e = ' '), ...); }
template <class T> void org(T l, T r) { while (l != r) cerr << ' ' << *l++; cerr << '\n'; }
#define debug(x...) dbg(#x, '=', x, '\n')
#define olist(x...) dbg(#x, '='), org(x)
#else
#define debug(...) ((void)0)
#define olist(...) ((void)0)
#endif
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define ff first
#define ss second

using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
using i128 = __int128;
using u128 = unsigned __int128;
using Pt = pair<int, int>;

template <class T> inline constexpr T inf = numeric_limits<T>::max() / 2;
constexpr int mod = 998244353;

template<class T> bool chmin(T &a, T b) { return (b < a and (a = b, true)); }
template<class T> bool chmax(T &a, T b) { return (a < b and (a = b, true)); }
template<class... T> int add(T... x) { int t{}; return (((t += x) %= mod), ...), t; }
template<class... T> int mul(T... x) { i64 t{1}; return (((t *= x) %= mod), ...), t; }

void solve() {
    int n, m, k;
    cin >> n >> m >> k;

    vector<i64> A(n + 4);
    vector<i64> B(n + 4);
    for (int i = 2; i < n + 2; i++) {
        cin >> A[i];
    }

    i64 ans = 0;
    for (int i = 0; i + 2 < n + 4; i++) {
        i64 t = B[i] + B[i + 1] + B[i + 2];
        for (int j = i + 2; j >= i; j--) {
            if (t < k and A[j]) {
                i64 s = min(k - t, A[j]);
                A[j] -= s;
                B[j] += s;
                t += s;
            }
        }
    }

    cout << reduce(all(B)) << '\n';
}

signed main() {
    cin.tie(0)->sync_with_stdio(false);
    cin.exceptions(cin.failbit);
    int T = 1;
    // cin >> T;
    while (T--) {
        solve();
    }
    return 0;
}