#include <bits/stdc++.h>
#define nmax 100001

using namespace std;

int n, q, mxx;
int v[ nmax ], tree[ 4 * nmax ];

void build(int nod, int left, int right){
    if (left == right){
        tree[ nod ] = v[ left ];
        return;
    }

    int mid = (left + right) / 2;

        build(nod * 2, left, mid);
        build(nod * 2 + 1, mid + 1, right);

    tree[ nod ] = max(tree[ nod * 2 ], tree[ nod * 2 + 1 ]);
}

void update(int nod, int left, int right, int poz, int val){
    if (left == right){
        tree[ nod ] = val;
        return;
    }

    int mid = (left + right) / 2;

    if (poz <= mid)
        update(nod * 2, left, mid, poz, val);
    else
        update(nod * 2 + 1, mid + 1, right, poz, val);

    tree[ nod ] = max(tree[ nod * 2 ], tree[ nod * 2 + 1 ]);
}

void solve(int nod, int left, int right, int x, int y){
    if (x <= left && right <= y){
        mxx = max(mxx, tree[ nod ]);
        return;
    }

    int mid = (left + right) / 2;

    if (x <= mid)
        solve(nod * 2, left, mid, x, y);
    if (y > mid)
        solve(nod * 2 + 1, mid + 1, right, x, y);
}


int main(){
    ios_base::sync_with_stdio(false);
    cin.tie( false );
    cout.tie( false );

    ifstream cin("arbint.in");
    ofstream cout("arbint.out");

    cin >> n >> q;

    for (int i = 1; i <= n; ++i)
        cin >> v[ i ];

    build(1, 1, n);

    for (int i = 0, x, y, z; i < q; ++i){
        cin >> z >> x >> y;

        if (z == 1)
            update(1, 1, n, x, y);
        else{
            mxx = -1;
            solve(1, 1, n, x, y);
            cout << mxx << '\n';
        }
    }
}