#include <bits/stdc++.h>
#include <bit>
#include <bitset>
#include <cstdint>
#include <iostream>

using namespace std;
// t2
#define gc getchar_unlocked
#define pii pair<long long, long long>
using ll = long long;
using cd = complex<double>;

const ll maxN = 1e6 + 10, maxM = 2e5 + 10, MAX = 2e6 + 10;
//const ll maxScore = 4294967295;
const ll mod = 1e9 + 7;
const double pi = acos(-1.0);
const double PI = acos(-1.0);
const double e = exp(1.0);
const ll naught = -100001;
const ll maxT = ceil(sqrt(maxN)) + 1;
const ll root_rec = 15311432;
const ll root_1 = 469870224;
const ll root_pw = (1 << 23);
const int K = 20;
const int g = 3;
const int LOGN = 20;
const int num1 = 16;
const int INF = 1e9;
//const ll is_query = -(1LL<<62)

ll seg[maxN * 4][2];

ll pref[maxN], prefL[maxN], n, m, k;

ll ril[maxN][2];

template <typename T> void fastInt(T& angka) {
    T kali = 1; angka = 0; char input = gc();
    while (!isdigit(input)) { if (input == '-') kali = -1; input = gc(); }
    while (isdigit(input)) angka = (angka << 3) + (angka << 1) + input - 48, input = gc();
    angka *= kali;
}

void fastStr(string& str) {
    str = "";
    char c = '0';
    while ((c = gc()) && (c != -1 && c != '\n' && c != '\t' && c != '\r' && c != ' ')) {
        str += c;
    }
}

ll powMod(ll x, ll y, ll p){
    ll res = 1;
    x %= p;
    if(!x) return 0;
    while (y > 0){
        if (y & 1) res = ((res % p) * (x % p)) % p;
        y = y >> 1;
        x = ((x % p) * (x % p)) % p;
    }
    return res % p;
}

ll inverseMod(ll x, ll p){
    return powMod(x, p - 2, p);
}

void upd(ll ind, ll l, ll r, ll i, ll j){
    if(r < i || i < l) return;
    if(l == r){
        assert(l == i);
        ril[l][j] ^= 1;
        seg[ind][j] = ril[l][j];
        return;
    }
    ll mid = (l + r) >> 1;
    upd(ind << 1, l, mid, i, j);
    upd(ind << 1 | 1, mid + 1, r, i, j);
    seg[ind][j] = seg[ind << 1][j] + seg[ind << 1 | 1][j];
}

ll query(ll ind, ll l, ll r, ll tl, ll tr, ll j){
    if(r < tl || tr < l) return 0;
    if(tl <= l && r <= tr) return seg[ind][j];
    ll mid = (l + r) >> 1;
    return query(ind << 1, l, mid, tl, tr, j) + query(ind << 1 | 1, mid + 1, r, tl, tr, j);
}

ll consider(ll x, ll y){
    if(x == -1) return y;
    if(y == -1) return x;
    return min(x, y);
}

ll clockwise(ll t1, ll t2){
    if(t1 == t2) return 0;
    ll asli = pref[max(t1, t2) - 1] - pref[min(t1, t2) - 1];
    if(t2 < t1){
        ll u = seg[1][0] - query(1, 1, n, t2, t1, 0);
        if(u == 0){
            return pref[n] - asli;
        }else{
            return -1;
        }
    }else{
        ll u = query(1, 1, n, t1, t2, 0);
        if(u == 0){
            return asli;
        }else{
            return -1;
        }
    }
}

ll counterclock(ll t1, ll t2){
    if(t1 == t2) return 0;
    return clockwise(t2, t1);
    //ll asli = pref[max(t1, t2) - 1] - pref[min(t1, t2) - 1];
    /*
    if(t2 < t1){
        ll k = t2 - 1;
        ll u = seg[1][0] - query(1, 1, n, t1, k, 0);
        if(u == 0){
            return pref[n] - pref[t1 - 1] + pref[k];
        }else{
            return -1;
        }
    }else{
        ll k = t1 - 1;
        if(k == 0) k = n;
        ll u = query(1, 1, n, t2, k, 0);
        if(u == 0){
            cout << t1 << "w " << t2 << endl;
            return pref[t2 - 1] - pref[k];
        }else{
            return -1;
        }
    }*/
}

ll case1(ll t1, ll t2){
    ll ans = -1;
    // clockwise
    ans = consider(ans, clockwise(t1, t2));
    //cout << "ans1: " << ans << endl;
    ans = consider(ans, counterclock(t1, t2));
    //cout << "ans2: " << ans << endl;

    if(seg[1][1] == 0){


    ll c1 = clockwise(t1, 1);
    ll cc1 = counterclock(t1, 1);

    ll k1 = consider(c1, cc1);

    ll c2 = clockwise(t1, k);
    ll cc2 = counterclock(t1, k);

    ll k2 = consider(c2, cc2);

    ll c3 = clockwise(1, t2);
    ll cc3 = counterclock(1, t2);

    ll k3 = consider(c3, cc3);

    ll c4 = clockwise(k, t2);
    ll cc4 = counterclock(k, t2);

    ll k4 = consider(c4, cc4);

    //cout << k1 << " " << k2 << " " << k3 << " " << k4 << " " << c3 << " " << cc3 <<  endl;

    if(k1 != -1 && k4 != -1) ans = consider(ans, k1 + k4 + prefL[m + 1]);
    if(k2 != -1 && k3 != -1) ans = consider(ans, k2 + k3 + prefL[m + 1]);
    }
    return ans;
}

ll case2(ll t1, ll t2){
    ll u1 = clockwise(t1, k);
    ll u2 = counterclock(t1, k);
    ll ans = -1;
    ll k1 = consider(u1, u2);
    if(k1 != -1 && query(1, 1, m + 1, t2 - n + 1, m + 1, 1) == 0){
        ans = consider(k1 + prefL[m + 1] - prefL[t2 - n], ans);
    }

    ll u3 = clockwise(t1, 1);
    ll u4 = counterclock(t1, 1);

    ll k2 = consider(u3, u4);
    if(k2 != -1 && query(1, 1, m + 1, 1, t2 - n, 1) == 0){
        ans = consider(k2 + prefL[t2 - n], ans);
    }
    return ans;
}

ll case3(ll t1, ll t2){
    return case2(t2, t1);
}

ll case4(ll t1, ll t2){
    if(t2 > t1) swap(t1, t2);
    ll u1 = clockwise(1, k);
    ll u2 = counterclock(1, k);

    ll k1 = consider(u1, u2);
    ll ans = -1;
    if(k1 != -1 && query(1, 1, m + 1, 1, t1 - n, 1) == 0 && query(1, 1, m + 1, t2 - n + 1, m + 1, 1) == 0){
        ans = consider(ans, k1 + prefL[t1 - n] + pref[m + 1] - pref[t2 - n]);
    }
    if(query(1, 1, m + 1, t1 - n + 1, t2 - n, 1) == 0){
        ans = consider(ans, prefL[t2 - n] - pref[t1 - n]);
    }
    return ans;
}

void solve(){
    ll q;
    fastInt(n); fastInt(k); fastInt(m); fastInt(q);
    for(int i = 1; i <= n; i++){
        ll x; fastInt(x);
        pref[i] = pref[i - 1] + x;
    }
    for(int i = 1; i <= m + 1; i++){
        ll x; fastInt(x);
        prefL[i] = prefL[i - 1] + x;
    }
    for(int i = 1; i <= q; i++){
        string s1; fastStr(s1);
        if(s1 == "c"){
            ll t; fastInt(t);
            upd(1, 1, n, t, 0);
        }else if(s1 == "x"){
            ll t; fastInt(t);
            t++;
            upd(1, 1, m + 1, t, 1);
        }else{
            ll t1, t2;
            fastInt(t1); fastInt(t2);
            ll u = -1;
            if(1 <= t1 && t1 <= n && 1 <= t2 && t2 <= n){
                u = case1(t1, t2);
            }else if(1 <= t1 && t1 <= n && n < t2 <= n + m){
                u = case2(t1, t2);
            }else if(n < t1 <= n + m && 1 <= t2 <= n){
                u = case3(t1, t2);
            }else{
                u = case4(t1, t2);
            }
            if(u == -1) cout << "impossible" << '\n';
            else cout << u << '\n';
        }
    }
}

int32_t main(){
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);
    cout.precision(10);
    //auto beg = high_resolution_clock::now();
    //cout << req(1e7 + 8) << '\n';
    //precalc();
    int t; t = 1;
    while(t--) solve();
    //auto en = high_resolution_clock::now();
    //auto dur = duration_cast<microseconds>(en - beg);
    //cout << dur.count() << endl;
    return 0;
}