#include <bits/stdc++.h>
//#pragma GCC optimize("Ofast","-funroll-loops")
//#pragma GCC target("sse4.1","sse4.2","ssse3","sse3","sse2","sse","avx2","avx","popcnt","tune=native")

using namespace std;

typedef long double ldb;
typedef long long i64;
typedef unsigned long long u64;
typedef unsigned int u32;
typedef pair<int, int> pii;

// priority_queue<int, vector<int>, greater<int>> minq;
// ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
// fflush(stdout);

const int inf = 1000000007;
const i64 prm = 998244353;
const i64 inf2 = ((i64)inf) * inf;
const i64 bone = 1;
const int maxn = 2000010;

inline int read(){
  int x=0,f=0; char ch=getchar();
  while(!isdigit(ch)) f|=(ch==45),ch=getchar();
  while(isdigit(ch)) x=(x<<3)+(x<<1)+(ch^48),ch=getchar();
  return f?-x:x;
}

struct S {
  i64 c[maxn];
  i64 tot;
  int sz;
  void up(int k, int w) {
    for (int i = k; i <= sz; i += i&-i) {
      c[i] += w;
    }
    tot += w;
  }
  i64 sum(int k) {
    i64 res = 0;
    for (int i = k; i > 0; i -= i&-i) {
      res += c[i];
    }
    return res;
  }
  i64 query(int u, int v) {
    if (u == v) {
      return 0;
    }
    if (u > v) {
      swap(u, v);
    }
    i64 ans = sum(v-1) - sum(u-1);
    return min(ans, tot-ans);
  }
} s[3];

int a[maxn][2], b[maxn][2];
vector<pii> A[maxn];
vector<pii> B[maxn];

int main() {
  int n = read(), k = read(), m = read(), q = read();

  s[0].tot = 0;
  s[0].sz = n;

  s[1].tot = 0;
  s[1].sz = k-1 + m+1;

  s[2].tot = 0;
  s[2].sz = n+1-k + m+1;

  for (int i = 1; i <= n; ++i) {
    a[i][0] = read();
    a[i][1] = inf;
    A[i].emplace_back(0, i);
    if (i < k) {
      A[i].emplace_back(1, i);
    } else {
      A[i].emplace_back(2, i+1-k + m+1);
    }
    for (auto e: A[i]) {
      s[e.first].up(e.second, a[i][0]);
    }
  }
  for (int i = 0; i <= m; ++i) {
    b[i][0] = read();
    b[i][1] = inf;
    B[i].emplace_back(1, m-i + k);
    B[i].emplace_back(2, i+1);// + n+1-k);
    for (auto e: B[i]) {
      s[e.first].up(e.second, b[i][0]);
    }
  }

  auto getvt = [&](int u) {
    vector<pii> vt;
    if (u == 1) {
      vt = A[1];
      for (auto e: B[0]) {
        vt.emplace_back(e);
      }
    }
    else if (u <= n) {
      vt = A[u];
    } else {
      vt = B[u - n];
    }
    return vt;
  };

  auto gao = [&](int u, int v) {
    int ans = inf;
    auto vtu = getvt(u), vtv = getvt(v);
    for (auto e1: vtu) {
      for (auto e2: vtv) if (e1.first == e2.first) {
        i64 res = s[e1.first].query(e1.second, e2.second);
        if (res < ans) {
          ans = res;
        }
      }
    }
    return ans;
  };

  while (q--) {
    static char t[12];
    scanf("%s", t);
    if (t[0] == 'c') {
      int i = read();
      for (auto e: A[i]) {
        s[e.first].up(e.second, a[i][1]-a[i][0]);
      }
      swap(a[i][0], a[i][1]);
    } else if (t[0] == 'x') {
      int j = read();
      for (auto e: B[j]) {
        s[e.first].up(e.second, b[j][1]-b[j][0]);
      }
      swap(b[j][0], b[j][1]);
    } else {
      int u = read(), v = read();
      int ans = gao(u, v);
      ans = min(gao(u, 1) + gao(1, v), ans);
      ans = min(gao(u, k) + gao(k, v), ans);
      if (ans >= inf) {
        puts("impossible");
      } else {
        printf("%d\n", ans);
      }
    }
  }
  return 0;
}