// 愚直解,確実にTLEする
#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, m;
    cin >> n >> m;
    vector<int> a(n), b;
    for(auto &&v : a) cin >> v;
    while(m--){
        int cmd;
        cin >> cmd;
        if(cmd == 1){
            int l, r, x, y;
            cin >> l >> r >> x >> y;
            l--;
            for(int i = l; i < r; i++){
                if(a[i] == x) a[i] = y;
            }
        }else{
            int l, r, k;
            cin >> l >> r >> k;
            l--;
            b = {a.begin() + l, a.begin() + r};
            sort(b.begin(), b.end());
            b.erase(unique(b.begin(), b.end()), b.end());
            int ng = 0, ok = 1 << 30;
            while(ng + 1 < ok){
                int mid = (ng + ok) / 2;
                mid -= upper_bound(b.begin(), b.end(), mid) - b.begin();
                (mid >= k ? ok : ng) = mid;
            }
            cout << ok << '\n';
        }
    }
}