#include <bits/stdc++.h>
using namespace std;
#define endl "\n"
const int N = 1e6 + 1009;
int n, m, k, q, c[N], C[N];
vector<int> ver[N];
int pre[N], suf[N], Pre[N], Suf[N], d1[N], d2[N];
set<int> s1, s2;
int check(int x) {
    if(x > n || x == k || x == 1) return true;
    return false;
}
int solve1(int x, int y) {
    if(x == y) return 0;
    if(x == n || (x > y && y != n)) swap(x, y);
    int idx = (x == 1 ? 0 : x - n);
    int idy = (y == k ? k : y - n - 1);
    //cout << x <<" " << y << " " << idx << " " << idy << endl;
    if(s2.lower_bound(idx) == s2.end() || *s2.lower_bound(idx) > idy) {
        return d1[y] - d1[x];
    } else return 0x3f3f3f3f;
}
int solve2(int x, int y) {
    if(x == y) return 0;
    if(x > y) swap(x, y);
    int idx = x;
    int idy = y - 1;
    int ans = 0x3f3f3f3f;
    if(s1.lower_bound(idx) == s1.end() || *s1.lower_bound(idx) > idy) {
        ans = min(ans, pre[y] - pre[x]);
    }
    if(s1.lower_bound(1) == s1.end() || *s1.lower_bound(1) > idx - 1) {
        if(s1.lower_bound(idy + 1) == s1.end()) {
            ans = min(ans, pre[x] + suf[y]);
           // cout << pre[x] << " " << suf[y] << " " << x << " " << y << endl;
        }
    }
    return ans;
}
int solve(int x, int y) {
    if(x == y) return 0;
    int ans = 0x3f3f3f3f;
    if(check(x) && check(y)) {
        ans = min(ans, solve1(x, y));
        ans = min(ans, solve1(x, 1) + solve2(1, k) + solve1(k, y));
        ans = min(ans, solve1(x, k) + solve2(k, 1) + solve1(1, y));
    } else if(check(x)) {
        ans = min(ans, solve1(x, 1) + solve2(1, y));
      //  cout<< ans<<" " << solve1(x, 1) <<  endl;
        ans = min(ans, solve1(x, k) + solve2(k, y));
    } else if(check(y)) {
        ans = min(ans, solve1(y, 1) + solve2(1, x));
        ans = min(ans, solve1(y, k) + solve2(k, x));
    } else {
        ans = min(ans, solve2(x, y));
        ans = min(ans, solve2(x, 1) + solve1(1, k) + solve2(k, y));
        ans = min(ans, solve2(x, k) + solve1(k, 1) + solve2(1, y));
    }
    return ans;
}
void work() {
    cin >> n >> k >> m >> q;
    for(int i = 1; i <= n; i ++) {
        cin >> c[i];
    }

    pre[1] = 0;
    for(int i = 2; i <= n; i ++) {
        pre[i] = pre[i - 1] + c[i - 1];
    }
    suf[n] = c[n];
    suf[1] = 0;
    for(int i = n - 1; i > 1; i --) {
        suf[i] = suf[i + 1] + c[i];
    }

    for(int i = 1; i <= m + 1; i ++) cin >> C[i];

    d1[1] = 0; d1[n + 1] = C[1];
    for(int i = n + 2; i <= n + m; i ++) d1[i] = d1[i - 1] + C[i - n];
    d1[k] = d1[n + m] + C[m + 1];

    d2[k] = 0; d2[n + m] = C[m + 1];
    for(int i = n + m - 1; i >= n + 1; i --) d2[i] = d2[i + 1] + C[i - n + 1];
    d2[1] = d2[n + 1] + C[1];

    for(int i = 1; i <= q; i ++) {
        string opt;
        cin >> opt;
        if(opt == "q") {
            int x, y;
            cin >> x >> y;
            int len = solve(x, y);
            if(len == 0x3f3f3f3f) cout << "impossible" << endl;
            else cout << solve(x, y) << endl;
        } else if(opt == "x") {
            int x;
            cin >> x;
            if(s2.count(x)) s2.erase(x);
            else s2.insert(x);
        } else if(opt == "c") {
            int x;
            cin >> x;
            if(s1.count(x)) s1.erase(x);
            else s1.insert(x);
        }
    }
}
signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int Case = 1;
    while(Case --) work();
    return 0;
}