#include <bits/stdc++.h>

using namespace std;

ifstream f("arbint.in");
ofstream g("arbint.out");

int N, M, m;
int vect[400067];

void creare(int nod, int left, int right, int poz, int Val)
{
    if (left == right)
    {
        vect[nod] = Val;
        return;
    }

    int mij = (left + right) / 2;
    if (poz <= mij)
        creare(2 * nod, left, mij, poz, Val);
    else
        creare(2 * nod + 1, mij + 1, right, poz, Val);

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

void creare2(int nod, int left, int right, int start, int finish)
{
    if (start <= left && right <= finish)
    {
        if (m < vect[nod])
            m = vect[nod];
        return;
    }

    int mij = (left + right) / 2;
    if (start <= mij) creare2(2 * nod, left, mij, start, finish);
    if (mij < finish) creare2(2 * nod + 1, mij + 1, right, start, finish);
}


int main()
{
    int X, A, B;
	f >> N >> M;
    for (int i = 1; i <= N; i++)
    {
        f >> X;
        creare(1, 1, N, i, X);
    }

    for (int i = 1; i <= M; i++)
    {
        f >> X >> A >> B;
        if (X == 0)
        {
            m = -1;
            creare2(1, 1, N, A, B);

            g << m << "\n";
        }
        else
        {
            creare(1, 1, N, A, B);
        }
    }
}