#include <fstream>

using namespace std;

ifstream fin("arbint.in");
ofstream fout("arbint.out");

int n, m, op, a, b, answer;
int tree[400005], v[100005];

void build_tree (int node, int left, int right){
    if (left == right){
        tree[node] = v[left];
    }
    else{
        int mid = (left + right)/2;
        build_tree(2 * node, left, mid);
        build_tree(2 * node + 1, mid + 1, right);
        tree[node] = max(tree[2*node], tree[2*node + 1]);
    }
}

void update_tree (int node, int left, int right, int a, int b){
    if (left == right){
        tree[node] = b;
    }
    else{
        int mid = (left + right)/2;
        if (a <= mid){
            update_tree(2 * node, left, mid, a, b);
        }
        else{
            update_tree(2 * node + 1, mid + 1, right, a, b);
        }
        tree[node] = max(tree[2*node], tree[2*node + 1]);
    }
}

void query_tree (int node, int left, int right, int a, int b){
    if (a <= left && b >= right){
        answer = max(answer, tree[node]);
    }
    else{
        int mid = (left + right)/2;
        if (a <= mid){
            query_tree(2 * node, left, mid, a, b);
        }
        if (b > mid){
            query_tree(2 * node + 1, mid + 1, right, a, b);
        }
    }
}

int main(){
    fin >> n >> m;
    for (int i=1; i<=n; i++){
        fin >> v[i];
    }
    build_tree(1, 1, n);
    while (m--) {
        fin >> op >> a >> b;
        if (op == 0){
            answer = -1;
            query_tree(1, 1, n, a, b);
            fout << answer << '\n';
        }
        else {
            update_tree(1, 1, n, a, b);
        }
    }
    return 0;
}