#include <bits/stdc++.h>

#define int int64_t

using namespace std;

const int N = 1e5 + 15;

int n;

int a[N];
int lazy[N * 4];
int t[N * 4][8];

void recalc (int v, int val) {
    int cnt[8]{};
    for (int i = 0; i < 8; i++) {
        cnt[i ^ val] = t[v][i];
    }
    for (int i = 0; i < 8; i++)
        t[v][i] = cnt[i];
}

void push (int v) {
    if ((v<<1|1) < 400'004 && lazy[v]) {
        lazy[v<<1|1] ^= lazy[v];
        lazy[v<<1] ^= lazy[v];
        recalc(v<<1, lazy[v]);
        recalc(v<<1|1, lazy[v]);
        lazy[v] = 0;
    }
}

void build (int v, int tl, int tr) {
    if (tl == tr) {
        t[v][a[tl]] = 1;
        return;
    }
    int tm = (tl + tr)>>1;
    build(v<<1, tl, tm);
    build(v<<1|1, tm + 1, tr);
    for (int i = 0; i < 8; i++)
        t[v][i] = t[v<<1][i] + t[v<<1|1][i];
}

void update (int v, int tl, int tr, int l, int r, int val) {
    if (l > r) {
        return;
    }
    push(v);
    if (l == tl && r == tr) {
        recalc(v, val);
        lazy[v] = val;
        return;
    }
    int tm = (tl + tr)>>1;
    update(v<<1, tl, tm, l, min(r, tm), val);
    update(v<<1|1, tm + 1, tr, max(l, tm + 1), r, val);
    for (int i = 0; i < 8; i++)
        t[v][i] = t[v<<1][i] + t[v<<1|1][i];
}

int get (int v, int tl, int tr, int l, int r, int val) {
    push(v);
    if (l > r || t[v][val] == 0)
        return LLONG_MAX;
    if (tl == tr) {
        return tl;
    }
    int tm = (tl + tr)>>1;
    int cur = get (v<<1, tl, tm, l, min(r, tm), val);
    if (cur != LLONG_MAX)
        return cur;
    return get(v<<1|1, tm + 1, tr, max(tm + 1, l), r, val);
}

int get (int left, int right) {
    int last[8][8];
    for (auto & i : last) {
        for (auto & j : i)
            j = LLONG_MAX;
    }
    for (int i = 0; i <= 7; i++) {
        last[0][i] = get(1, 0, n - 1, left, right, i);
        if (i > 0)
            last[0][i] = min(last[0][i], last[0][i - 1]);
    }
    for (int len = 1; len <= 7; len++) {
        for (int j = len; j <= 7; j++) {
            last[len][j] = min(get(1, 0, n - 1, last[len - 1][j - 1], right, j), last[len][j - 1]);
        }
    }
    for (int len = 7; len > -1; len--) {
        for (int i = 0; i <= 7; i++) {
            if (last[len][i] != LLONG_MAX)
                return len + 1;
        }
    }
    return 1;
}

int32_t main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int q;
    cin >> n >> q;
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    build(1, 0, n - 1);
    while (q--) {
        string tp;
        cin >> tp;
        if (tp == "xor") {
            int l, r, x;
            cin >> l >> r >> x;
            l--, r--;
            update(1, 0, n - 1, l, r, x);
        } else {
            int l, r;
            cin >> l >> r;
            l--, r--;
            cout << get(l, r) << '\n';
        }
    }
}