#include <bits/stdc++.h>

using namespace std;

int32_t main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);
    int n, q;
    cin >> n >> q;
    vector <int> a(n);
    for(auto &i: a)
        cin >> i;
    vector<multiset<int>> v (8);
    for(int i = 0; i < n; i++)
        v[a[i]].insert(i);
    while(q--){
        string s;
        cin >> s;
        if(s == "xor"){
            int l, r, u;
            cin >> l >> r >> u;
            l--, r--;
            for(int i = l; i <= r; i++){
                v[a[i]].erase(i);
                a[i] ^= u;
                v[a[i]].insert(i);
            }
        }
        else{
            int l, r;
            cin >> l >> r;
            l--, r--;
            int ans = 0;
            for(int i = 0; i <= 7; i++) {
                if(v[i].lower_bound(l) == v[i].end())
                    continue;
                int now_z = *v[i].lower_bound(l);
                if(now_z > r)
                    continue;
                ans = max(ans, 1);
                for (int j = i + 1; j <= 7; j++){
                    if(v[j].upper_bound(now_z) == v[j].end())
                        continue;
                    int now_o = *v[j].upper_bound(now_z);
                    if(now_o > r)
                        continue;
                    ans = max(ans, 2);
                    for(int k = j + 1; k <= 7; k++){
                        if(v[k].upper_bound(now_o) == v[k].end())
                            continue;
                        int now_two = *v[k].upper_bound(now_o);
                        if(now_two > r)
                            continue;
                        ans = max(ans, 3);
                        for(int m = k + 1; k <= 7; k++){
                            if(v[m].upper_bound(now_two) == v[m].end())
                                continue;
                            int now_t = *v[m].upper_bound(now_two);
                            if(now_t > r)
                                continue;
                            ans = max(ans, 4);
                            for(int o = m + 1; o <= 7; o++){
                                if(v[o].upper_bound(now_t) == v[o].end())
                                    continue;
                                int now_four = *v[o].upper_bound(now_t);
                                if(now_four > r)
                                    continue;
                                ans = max(ans, 5);
                                for(int p = o + 1; p <= 7; p++){
                                    if(v[p].upper_bound(now_four) == v[p].end())
                                        continue;
                                    int now_f = *v[p].upper_bound(now_four);
                                    if(now_f > r)
                                        continue;
                                    ans = max(ans, 6);
                                    for(int t = p + 1; t <= 7; t++){
                                        if(v[t].upper_bound(now_f) == v[t].end())
                                            continue;
                                        int now_six = *v[t].upper_bound(now_f);
                                        if(now_six > r)
                                            continue;
                                        ans = max(ans, 7);
                                        for(int u = t + 1; u <= 7; u++){
                                            if(v[u].upper_bound(now_six) == v[u].end())
                                                continue;
                                            int now_s = *v[u].upper_bound(now_six);
                                            if(now_s > r)
                                                continue;
                                            ans = max(ans, 8);
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
            cout << ans << '\n';
        }
    }
}