#include <bits/stdc++.h>
#define fst first
#define snd second
using namespace std;
typedef long long ll;
const int N = 1000010;
const int INF = 1e9;
int n, k, m, q;
int c[N], sc[N];
int x[N], sx[N];
ll tr1[N], tr2[N];

void add(ll *tr, int a, int w) {
	for(; a <= max(n, m + 1); a += a & -a) tr[a] += w;
}
ll ask(ll *tr, int a) {
	ll w = 0;
	for(; a; a -= a & -a) w += tr[a];
	return w;
}
ll Out(int a, int b) {
	if(a > b) swap(a, b);
	return min(ask(tr1, b - 1) - ask(tr1, a - 1), ask(tr1, n) - ask(tr1, b - 1) + ask(tr1, a - 1));
}
bool type1(int a) {
	return a <= n && a >= 1;
}
bool type2(int a) {
	return a > n;
}
ll dis(int a, int b) {
	if(a > b) swap(a, b);
	if(a == b) return 0;
	if(a == 1) {
		if(type1(b)) {
			ll res = Out(a, b);
			res = min(res, ask(tr2, m + 1) + Out(k, b));
			return res;
		}
		else {
			ll res = ask(tr2, b - n);
			res = min(res, ask(tr2, m + 1) - ask(tr2, b - n) + Out(1, k));
			return res;
		}
	}
	if(a == k || b == k) {
		if(b == k) swap(a, b);
		if(type1(a)) {
			ll res = Out(a, b);
			res = min(res, ask(tr2, m + 1) + Out(1, b));
			return res;
		}
		else {
			ll res = ask(tr2, m + 1) - ask(tr2, b - n);
			res = min(res, ask(tr2, b - n) + Out(1, k));
			return res;
		}
	}
	if(type1(a) && type1(b)) {
		ll res = Out(a, b);
		res = min(res, dis(a, k) + dis(k, b));
		res = min(res, dis(a, 1) + dis(1, b));
		return res;
	}
	if(type2(a) && type2(b)) {
		ll res = ask(tr2, b - n + 1) - ask(tr2, a - n);
		res = min(res, dis(a, k) + dis(k, b));
		res = min(res, dis(a, 1) + dis(1, b));
		return res;
	}
	ll res = INF * 100ll;
	res = min(res, dis(a, k) + dis(k, b));
	res = min(res, dis(a, 1) + dis(1, b));
	return res;
}
int main() {
	ios::sync_with_stdio(0); cin.tie(nullptr);
	cin >> n >> k >> m >> q;
	for(int i = 1; i <= n; i++) cin >> c[i];
	for(int i = 1; i <= n; i++) {
		sc[i] = 1, add(tr1, i, c[i]);
	}
	for(int i = 1; i <= m + 1; i++) {
		cin >> x[i];
		sx[i] = 1, add(tr2, i, x[i]);
	}
	for(; q; --q) {
		char op[5]; int a, b; cin >> op;
		if(op[0] == 'c') {
			cin >> a;
			if(sc[a] == 0) {
				add(tr1, a, -INF);
				add(tr1, a, c[a]);
				sc[a] = 1;
			}
			else {
				add(tr1, a, -c[a]);
				add(tr1, a, INF);
				sc[a] = 0;
			}
		}
		else if(op[0] == 'x') {
			cin >> a, ++a;
			if(sx[a] == 0) {
				add(tr2, a, -INF);
				add(tr2, a, x[a]);
				sx[a] = 1;
			}
			else {
				add(tr2, a, -x[a]);
				add(tr2, a, INF);
				sx[a] = 0;
			}
		}
		else {
			cin >> a >> b;
			ll value = dis(a, b);
			if(value >= INF) cout << "impossible\n";
			else cout << value << "\n";
		}
	}
	return 0;
}