#include <bits/stdc++.h>

using namespace std;

#define int long long
#define forn(i,n) for(int i = 0; i <(int)n; ++i)
#define vi vector<int>
#define debug(x)    cout << #x << " : " << x << endl;

const int MOD = 1000000007;
//const int MOD = 998244353;

int fen[3][1000005]; // clow, chigh, x
int n, k, m, q;

void add(int x, int v, int f) {
    for (int i = x; i <= 1000000; i += i & -i) {
        fen[f][i] += v;
    }
}

int sum(int x, int f) {
    int ans = 0;
    for (int i = x; i > 0; i -= i & -i) {
        ans += fen[f][i];
    }
    return ans;
}


bool X[1000005], C[1000005];

void init() {
    for (int i = 0; i <= 1000003; ++i) {
        X[i] = C[i]  =1;
    }
    memset(fen, 0, sizeof(fen));
}
void togglex(int x) {
    if (X[x]) {
        add(x+1, 1e12, 2);
    }
    else {
        add(x+1, -1e12, 2);
    }

    X[x] = !X[x];
}

void togglec(int c) {
    int p = c >= k;
    int cc = c - (k - 1) * p;

    if (C[c]) {
        add(cc, 1e12, p);
    }
    else {
        add(cc, -1e12, p);
    }

    C[c] = !C[c];
}

int query(int l, int r) {
    int ans = LLONG_MAX;
    // direct
    if (l != 1 && l != k && r != 1 && r != k) {
        if (1 <= l && l < k && 1 < r && r < k) {
            int ll = min(l, r);
            int rr = max(l, r);

            ans = min(ans, sum(rr, 0) - sum(ll, 0));
        }
        else if (k < l && l <= n && k < r && r <= n) {
            int ll = min(l, r) - k;
            int rr = max(l, r) - k;

            ans = min(ans, sum(rr, 1) - sum(ll, 1));
        }
        else if (n < l && l <= n+m && n < r && r <= n+m) {
            int ll = min(l, r) - n;
            int rr = max(l, r) - n;

            ans = min(ans, sum(rr, 2) - sum(ll, 2));
        }
    }

    int lto1;
    if (1 <= l && l <= k) {
        lto1 = sum(l, 0);
    }
    else if (k < l && l <= n) {
        lto1 = sum(n-k+1, 1) - sum(l-k, 1);
    }
    else if (n < l && l <= n+m) {
        lto1 = sum(l-n, 2);
    }

    int rto1;
    if (1 <= r && r <= k) {
        rto1 = sum(r, 0);
    }
    else if (k < r && r <= n) {
        rto1 = sum(n-k+1, 1) - sum(r-k, 1);
    }
    else if (n < r && r <= n+m) {
        rto1 = sum(r-n, 2);
    }

    int ltok;
    if (1 <= l && l <= k) {
        ltok = sum(k, 0) - sum(l, 0);
    }
    else if (k < l && l <= n) {
        ltok = sum(l-k, 1);
    }
    else if (n < l && l <= n+m) {
        ltok = sum(m+1, 2) - sum(l-n, 2);
    }

    int rtok;
    if (1 <= r && r <= k) {
        rtok = sum(k, 0) - sum(r, 0);
    }
    else if (k < r && r <= n) {
        rtok = sum(r-k, 1);
    }
    else if (n < r && r <= n+m) {
        rtok = sum(m+1, 2) - sum(r-n, 2);
    }

    int kto1;
    kto1 = min(sum(k, 0), min(sum(n-k+1, 1), sum(m+1, 2)));

    // cout << m << "  " << sum(m+1, 2) << endl;

    // cout << lto1 << ' ' << ltok << ' ' << rto1 << ' ' << rtok << ' ' << kto1 << '\n';


    // via 1
    ans = min(ans, lto1 + rto1);
    // via k
    ans = min(ans, ltok + rtok);
    // via 1 - k
    ans = min(ans, lto1 + kto1 + rtok);
    // via k - 1
    ans = min(ans, ltok + kto1 + rto1);

    if (ans >= 1e12) {
        return -1;
    }
    return ans;
}

void solve() {
    cin >> n >> k >> m >> q;
    init();
    forn(i, n) {
        int x;
        cin >> x;
        if (i < k- 1) {
            add(i+1, x, 0);
        }
        else {
            add(i+2-k, x, 1);
        }
    }
    forn(i, m+1) {
        int x;
        cin >> x;
        add(i+1, x, 2);
    }

    forn(i, q) {
        char c;
        cin >> c;
        if (c == 'q') {
            int l, r;
            cin >> l >> r;
            int ans = query(l, r);
            if (ans == -1) {
                cout << "impossible\n";
            }
            else {
                cout << ans << '\n';
            }
        }
        else if (c == 'c') {
            int x;
            cin >> x;
            togglec(x);
        }
        else if (c == 'x') {
            int x;
            cin >> x;
            togglex(x);
        }
    }
}


int32_t main()
{
    ios::sync_with_stdio(false); cin.tie(NULL);
    int tc = 1;
    // cin >> tc;
    while(tc--) {
        solve();
    }
    return 0;
}