#include <fstream>
#include <algorithm>
using namespace std;

ifstream is("arbint.in");
ofstream os("arbint.out");

int n, m, x, y, z, rez, arb[400004];

void Up( int N, int L, int R, int poz, int val );
void Querry( int N, int L, int R, int a, int b );

int main()
{
    is >> n >> m;
    for ( int i = 1; i <= n; i++ )
    {
        is >> x;
        Up( 1, 1, n, i, x );
    }
    for ( int i = 1; i <= m; i++ )
    {
        is >> x >> y >> z;
        if ( x == 0 )
        {
            rez = -1;
            Querry( 1, 1, n, y, z );
            os << rez << '\n';
        }
        else
            Up( 1, 1, n, y, z );
    }
    is.close();
    os.close();
    return 0;
}

void Up( int N, int L, int R, int poz, int val )
{
    if ( L == R )
        arb[N] = val;
    else
    {
        int mij = ( L + R ) / 2;
        if ( poz <= mij )
            Up( 2*N, L, mij, poz, val );
        else
            Up( 2*N + 1, mij + 1, R, poz, val );
        arb[N] = max( arb[2*N], arb[2*N+1] );
    }
}

void Querry( int N, int L, int R, int a, int b )
{
    if ( a <= L && R <= b )// intervalul [L, R] se afla in intervalul [a, b]
    {
        rez = max( rez, arb[N] );
        return;
    }
    int mij = ( L + R ) / 2;
    if ( a <= mij ) Querry( 2*N, L, mij, a, b );
    if ( mij < b ) Querry( 2*N + 1, mij + 1, R, a, b );
}