#include <iostream>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <cstdlib>
#include <cmath>
#include <cstring>
#include <iomanip>
using namespace std;

const int N = 1e6 + 5, inf = 1e9;
#define pb push_back
#define mp make_pair
#define ll long long
#define ff first
#define ss second
#define all(a) a.begin(),a.end()
#define sz(x) (int)x.size()
typedef vector<int> vi;
typedef pair<int,int> ii;
typedef vector<ii> vii;
int n, k, m, q;
int a[N], b[N];

ll t[4 * N];

void update(int v, int l, int r, int x, int k){
    if(l > x || r < x)return;
    if(l == x && r == x){
        t[v] = k;
        return;
    }
    int mid = (l + r) / 2;
    update(v * 2, l, mid, x, k);
    update(v * 2 + 1, mid + 1, r, x, k);
    t[v] = t[v * 2] + t[v * 2 + 1];
}
ll get(int v, int l, int r, int ql, int qr){
    if(ql > qr)return 0ll;
    if(l > qr || r < ql)return 0ll;
    if(ql <= l && r <= qr)return t[v];
    int mid = (l + r) / 2;
    return get(v * 2, l, mid, ql, qr) + get(v * 2 + 1, mid + 1, r, ql, qr);
}
ll f(int u, int v){
    return get(1, 1, n + m + 1, u, v);
}
void solve(){
    cin >> n >> k >> m >> q;
    for(int i = 1; i <= n; i++){
        cin >> a[i];
        update(1, 1, n + m + 1, i, a[i]);
    }
    for(int i = 0; i <= m; i++){
        cin >> b[i];
        update(1, 1, n + m + 1, n + i + 1, b[i]);
    }
    while(q--){
        char type;
        cin >> type;
        if(type == 'q'){
            int u, v; cin >> u >> v;
            if(u > v)swap(u, v);
            ll res = inf;
            //u->v
            res = min(res, min(f(u, v - 1), f(1, u - 1) + f(v, n)));
            //u->k->1->v
            ll cur = min({f(min(u, k), max(u, k) - 1), f(1, u - 1) + f(n + 1, n + m + 1), f(u, n) + f(1, k - 1), f(1, u - 1) + f(k, n)}); // u->k
            cur += min({f(n + 1, n + m + 1), f(k, n), f(1, k - 1)});
            cur += min(f(1, v - 1), f(v, n));
            res = min(res, cur);
            //u->1->k->v
            cur = min(f(1, u - 1), f(u, n));
            cur += min({f(n + 1, n + m + 1), f(k, n), f(1, k - 1)});
            cur += min({f(min(v, k), max(v, k) - 1), f(1, v - 1) + f(n + 1, n + m + 1), f(k, n) + f(1, v - 1), f(1, k - 1) + f(v, n)});
            res = min(res, cur);
            
            if(res == inf){
                cout << "impossible\n";
            } else {
                cout << res << '\n';
            }
        } else if(type == 'c'){
            int i; cin >> i;
            if(f(i, i) == inf){
                update(1, 1, n + m + 1, i, a[i]);
            } else {
                update(1, 1, n + m + 1, i, inf);
            }
        } else if(type == 'x'){
            int j; cin >> j;
            if(f(n + 1 + j, n + 1 + j) == inf){
                update(1, 1, n + m + 1, n + 1 + j, b[j]);
            } else {
                update(1, 1, n + m + 1, n + 1 + j, inf);
            }
        }
    }
}

int main(){
    ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    int t = 1;
    // cin >> t;
    while(t--){
        solve();
    }
    return 0;
}