#pragma GCC optimize("Ofast")
#pragma GCC optimize("O3")

#include <bits/stdc++.h>

#define el '\n'
#define F first
#define S second

typedef long long ll;
typedef long double ld;
typedef __int128 bigInt;

using namespace std;

const int N = 1e6 + 5, INF = 1e9 + 5, mod = 1e9 + 7, LOG = 21, SQ = 500;

int n, k, m, q, c[N], x[N];

struct SegmentTree {
    vector<ll> tree;
    ll neutral;

    SegmentTree(){}

    SegmentTree(int sz) {
        tree.assign(4 * sz, 0);
        neutral = 0;
    }

    ll merge(ll &u, ll &v) {
        return u + v;
    }

    void build(int node, int start, int end, int a[]) {
        if (start == end)
            return tree[node] = a[start], void();

        int m = (start + end) >> 1;

        build(2 * node, start, m, a);
        build(2 * node + 1, m + 1, end, a);

        tree[node] = merge(tree[2 * node], tree[2 * node + 1]);
    }

    void set(int node, int start, int end, int idx, ll val) {
        if (start == end)
            return tree[node] = val, void();

        int m = (start + end) >> 1;

        if (idx <= m)
            set(2 * node, start, m, idx, val);
        else
            set(2 * node + 1, m + 1, end, idx, val);

        tree[node] = merge(tree[2 * node], tree[2 * node + 1]);
    }

    ll query(int node, int start, int end, int left, int right) {
        if (end < left or start > right or left > right)
            return neutral;

        if (left <= start and end <= right)
            return tree[node];

        int m = (start + end) >> 1;
        ll l = query(2 * node, start, m, left, right);
        ll r = query(2 * node + 1, m + 1, end, left, right);
        return merge(l, r);
    }
}stc, stx;

ll pathcw(int u, int v) {
    if (u == v) {
        return 0;
    }
    ll ret = 0;
    if (v > u) {
        // direct u -> v
        ret += stc.query(1, 1, n, u, v - 1);
    }
    else {
        // u to one, one to v
        ret += stc.query(1, 1, n, u, n);
        ret += stc.query(1, 1, n, 1, v - 1);
    }
    return ret;
}

ll pathccw(int u, int v) {
    if (u == v) {
        return 0;
    }
    ll ret = 0;
    if (v < u) { // haroh lel soghayar
        // direct u -> v
        ret += stc.query(1, 1, n, v, u - 1);
    }
    else {
        // one to u, v to one
        ret += stc.query(1, 1, n, 1, u - 1);
        ret += stc.query(1, 1, n, v, n);
    }
    return ret;
}

ll pathx(int u, int v) {
    if (u == v) {
        return 0;
    }
    if (u == 1) {
        u = 0;
    }
    if (v == 1) {
        v = 0;
    }
    if (u == k) {
        u = m + 1;
    }
    if (v == k) {
        v = m + 1;
    }
    if (u > v) {
        swap(u, v);
    }

    return stx.query(1, 0, m, u, v - 1);
}

void doWork() {
    cin >> n >> k >> m >> q;

    for (int i = 1; i <= n; i++) {
        cin >> c[i];
    }

    for (int i = 0; i <= m; i++) {
        cin >> x[i];
    }

    stc = SegmentTree(n);
    stc.build(1, 1, n, c);

    stx = SegmentTree(m + 1);
    stx.build(1, 0, m, x);

    while (q--) {
        char type;
        cin >> type;
        if (type == 'q') {
            int u, v;
            cin >> u >> v;

            bool uc = 0, ux = 0, vc = 0, vx = 0;
            (u <= n ? uc = 1 : ux = 1);
            (v <= n ? vc = 1 : vx = 1);

            ll ans;

            if (uc and vc) { // cc
                ans = min(pathcw(u, v), pathccw(u, v));

//                cout << "init ans " << ans << el;

                ll uone = min(pathcw(u, 1), pathccw(u, 1));
//                cout << "uone " << uone << " " << pathcw(u, 1) << ' ' << pathccw(u, 1) << el;
                ll onek = pathx(1, k);
//                cout << "onek " << onek << el;
                ll kv = min(pathcw(k, v), pathccw(k, v));
//                cout << "kv " << kv << el;

                ll uk = min(pathcw(u, k), pathccw(u, k));
//                cout << "uk " << uk << el;
                ll kone = pathx(k, 1);
//                cout << "kone " << kone << el;
                ll onev = min(pathcw(1, v), pathccw(1, v));
//                cout << "onev " << onev << endl;

                ans = min({
                    ans,
                    uone + onek + kv,
                    uk + kone + onev
                });
            }
            else if (ux and vx) { // xx
                ans = pathx(u, v);

                ll uone = pathx(u, 1);
                ll onek = min(pathcw(1, k), pathccw(1, k));
                ll kv = pathx(k, v);

                ll uk = pathx(u, k);
                ll kone = min(pathcw(1, k), pathccw(1, k));
                ll onev = pathx(1, v);

                ans = min({
                    ans,
                    uone + onek + kv,
                    uk + kone + onev
                });
            }
            else { // cx
                if (ux) {
                    swap(u, v);
                }

                ll uone = min(pathcw(u, 1), pathccw(u, 1));
                ll onev = pathx(1, v);

                ll uk = min(pathcw(u, k), pathccw(u, k));
                ll kv = pathx(k, v);

                ans = min(uone + onev, uk + kv);
            }

            if (ans < 1e9) {
                cout << ans << el;
            }
            else {
                cout << "impossible" << el;
            }
        }
        else if (type == 'c') {
            int i;
            cin >> i;
            // update edge i in c with INF
            int val = stc.query(1, 1, n, i, i);
            if (val < INF) {
                stc.set(1, 1, n, i, INF);
            }
            else {
                stc.set(1, 1, n, i, c[i]);
            }
        }
        else if (type == 'x') {
            int i;
            cin >> i;
            // update edge i in x with INF
            int val = stx.query(1, 0, m, i, i);
            if (val < INF) {
                stx.set(1, 0, m, i, INF);
            }
            else {
                stx.set(1, 0, m, i, x[i]);
            }
        }
    }
}

int main() {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);

    int tests = 1;
//    cin >> tests;
    for (int i = 1; i <= tests; i++) {
        doWork();
    }
}