#include<bits/stdc++.h>
#define int long long
#define endl '\n'
using namespace std;
const int N = 1e6 + 5;
const int INF = 1e18;
bool visc[N], visx[N];
int c[N], x[N];
struct B{
    int n;
    vector<int> bit;
    void init(int _n){
        n = _n;
        bit = vector<int>(n+1, 0);
    }
    int lowbit(int x){ return (x&-x); }
    void update(int x, int v){
        for(; x<=n; x+=lowbit(x)){
            bit[x] += v;
        }
    }
    int query(int x){
        int ret = 0;
        for(; x; x-=lowbit(x)){
            ret += bit[x];
        }
        return ret;
    }
}BIT, BIT2;
void solve(){
    int n, k, m, q;
    cin >> n >> k >> m >> q;
    int s = 0;
    for(int i=1; i<=n; i++){
        cin >> c[i];
        c[i] += s;
        s = c[i];
        visc[i] = 1;
    }
    s = 0;
    for(int i=1; i<=m+1; i++){
        cin >> x[i];
        x[i] += s;
        s = x[i];
        visx[i] = 1;
    }
    BIT.init(n);
    BIT2.init(m+1);
    for(int i=0; i<q; i++){
        char ch; int a, b;
        cin >> ch;
        if(ch == 'q'){
            cin >> a >> b;
            if(a > b) swap(a, b);
            int k1=0, k2=0, k3=0, k4=0, k5=-1, k6=-1;
            int l1, l2, l3, l4;
            int L, M, R;
            int ll, mm, rr;
            L = BIT.query(n) - BIT.query(k-1);
            ll = c[n] - c[k-1];
            M = BIT2.query(m+1);
            mm = x[m+1];
            R = BIT.query(k-1);
            rr = c[k-1];
            if(1 <= a && a <= k){
                k1 = BIT.query(a-1);
                l1 = c[a-1];
                k2 = BIT.query(k-1) - BIT.query(a-1);
                l2 = c[k-1] - c[a-1];
            }
            else if(k <= a && a <= n){
                k1 = BIT.query(n) - BIT.query(a-1);
                l1 = c[n] - c[a-1];
                k2 = BIT.query(a-1) - BIT.query(k-1);
                l2 = c[a-1] - c[k-1];
            }
            else{
                k1 = BIT2.query(a-n);
                l1 = x[a-n];
                k2 = BIT2.query(m+1) - BIT2.query(a-n);
                l2 = x[m+1] - x[a-n];
            }
            if(1 <= b && b <= k){
                k3 = BIT.query(b-1);
                l3 = c[b-1];
                k4 = BIT.query(k-1) - BIT.query(b-1);
                l4 = c[k-1] - c[b-1];
            }
            else if(k <= b && b <= n){
                k3 = BIT.query(n) - BIT.query(b-1);
                l3 = c[n] - c[b-1];
                k4 = BIT.query(b-1) - BIT.query(k-1);
                l4 = c[b-1] - c[k-1];
            }
            else{
                k3 = BIT2.query(b-n);
                l3 = x[b-n];
                k4 = BIT2.query(m+1) - BIT2.query(b-n);
                l4 = x[m+1] - x[b-n];
            }
            int ans = INF;
            if(k1 + k3 == 0)
                ans = min(ans, l1+l3);
            if(k2 + k4 == 0)
                ans = min(ans, l2+l4);
            if(k1 + k4 == 0){
                int sum = l1+l4;
                if(L == 0)
                    ans = min(ans, sum+ll);
                if(M == 0)
                    ans = min(ans, sum+mm);
                if(R == 0)
                    ans = min(ans, sum+rr);
            }
            if(k2 + k3 == 0){
                int sum = l2 + l3;
                if(L == 0)
                    ans = min(ans, sum+ll);
                if(M == 0)
                    ans = min(ans, sum+mm);
                if(R == 0)
                    ans = min(ans, sum+rr);
            }
            if(1 <= a && a <= n && 1 <= b && b <= n){
                if(BIT.query(b-1) - BIT.query(a-1) == 0)
                    ans = min(ans, c[b-1]-c[a-1]);
                if(BIT.query(n) - BIT.query(b-1) + BIT.query(a-1) == 0)
                    ans = min(ans, c[n]-c[b-1]+c[a-1]);
            }
            if(n+1 <= a && a <= n+m+1 && n+1 <= b && b <= n+m+1){
                if(BIT2.query(b-n) - BIT2.query(a-n-1) == 0)
                    ans = min(ans, x[b-n]-x[a-n-1]);
            }
            
            // cout << l1 << " " << l2 << " " << l3 << " " << l4 << endl;
            if(ans == INF) cout << "impossible\n";
            else cout << ans << endl;
        }
        else if(ch == 'c'){
            cin >> a;
            if(visc[a])
                BIT.update(a, 1);
            else 
                BIT.update(a, -1);
            visc[a] ^= 1;
        }
        else{
            cin >> a;
            a++;
            if(visx[a])
                BIT2.update(a, 1);
            else
                BIT2.update(a, -1);
            visx[a] ^= 1;
        }
    }
}
signed main(){
    ios_base::sync_with_stdio(0); cin.tie(0);
    int T = 1;
    // cin >> T;
    while(T--){
        solve();
    }
}