#include <bits/stdc++.h>
using namespace std;
ifstream in("arbint.in");
ofstream out("arbint.out");

int main()  {
    int N, M;
    in >> N >> M;
    vector<int> a(N);
    for(int i = 0; i < N; ++i) {
        in >> a[i];
    }
    vector<int> block(N);
    int blockSize = (int) sqrt(N);
    for(int i = 0; i < N; ++i) {
        block[i] = i / blockSize;
    }
    vector<int> maxByBlock(N / blockSize + 6);
    for(int i = 0; i < N; ++i) {
        int whatBlock = block[i];
        maxByBlock[whatBlock] = max(maxByBlock[whatBlock], a[i]);
    }
    for(int i = 0; i < M; ++i) {
        int op;
        in >> op;
        if(op == 0) {
            int L, R;
            in >> L >> R;
            L--, R--;
            int ans = -2e9;
            while(L < R && block[L] == block[L + 1]) {
                ans = max(ans, a[L]);
                L++;
            }
            while(R > L && block[R] == block[R - 1]) {
                ans = max(ans, a[R]);
                R--;
            }
            if(L == R) {
                ans = max(ans, a[L]);
                L++;
            } else {
                ans = max(ans, a[L]);
                ans = max(ans, a[R]);
                L++;
                R--;
            }
            if(L <= R) {
				for(int j = block[L]; j <= block[R]; ++j) {
					ans = max(ans, maxByBlock[j]);
				}
			}
            out << ans << '\n';
        } else {
            int pos, x;
            in >> pos >> x;
            pos--;
            int L = block[pos] * blockSize;
            int R = min( (block[pos] + 1) * blockSize - 1, N - 1);
            a[pos] = x;
            maxByBlock[ block[pos] ] = -2e9;
            for(int j = L; j <= R; ++j) {
                maxByBlock[ block[j] ] = max(maxByBlock[ block[j] ], a[j]);
            }
        }
    }
}