#include <bits/stdc++.h>

using namespace std;

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

const int NMAX = 100002;
int n, m, ans;
int aint[4 * NMAX];
int a[NMAX];

int Leftson(int node)
{
    return 2 * node;
}

int Rightson(int node)
{
    return 2 * node + 1;
}
void Build(int nod, int left, int right)
{
    if(left == right)
    {
        aint[nod] = a[left];
        return;
    }
    int mid = (left + right) / 2;
    Build(Leftson(nod), left, mid);
    Build(Rightson(nod), mid + 1, right);
    aint[nod] = max(aint[Leftson(nod)], aint[Rightson(nod)]);
}

void Update(int nod, int left, int right, int poz, int val)
{
    if(left == right)
    {
        a[poz] = val;
        aint[nod] = val;
        return;
    }
    int mid = (left + right) / 2;
    if(poz <= mid)
        Update(Leftson(nod), left, mid, poz, val);
    else
        Update(Rightson(nod), mid + 1, right, poz, val);
    aint[nod] = max(aint[Leftson(nod)], aint[Rightson(nod)]);

}

void Query(int nod, int left, int right, int lquery, int rquery)
{
    if(lquery <= left && rquery >= right)
    {
        ans = max(ans, aint[nod]);
        return;
    }
    int mid = (left + right) / 2;
    if(lquery <= mid)
        Query(Leftson(nod), left , mid, lquery, rquery);
    if(rquery > mid)
        Query(Rightson(nod), mid + 1, right, lquery, rquery);
}
void Citire()
{
    int i, op, x, y;
    fin >> n >> m;
    for(i = 1;i <= n;i++)
        fin >> a[i];
    Build(1, 1, n);
    while(m--)
    {
        fin >> op >> x >> y;
        if(op == 1)
            Update(1, 1, n, x, y);
        else
        {
            ans = -1;
            Query(1, 1, n, x, y);
            fout << ans << "\n";
        }
    }
}
int main()
{
    Citire();
    return 0;
}