#include <fstream>
#include <cmath>
#define amax(a,b) a=max(a,b)
using namespace std;
ifstream f ("arbint.in");
ofstream g ("arbint.out");
const int nmax=1e6+3;
int n,t,d[nmax],v[nmax],caz,a,b;
void precalc()
{
    int sq=sqrt(n);
    int tp=n/sq;
    for(int i=0;i<tp;++i)
    {
        for(int j=i*sq+1;j<=(i+1)*sq;++j) amax(d[i],v[j]);
    }
}
void change(int a,int b)
{
    v[a]=b;
    int sq=sqrt(n);
    int poz=a/sq-(a%sq==0);
    d[poz]=0;
    for(int i=poz*sq+1;i<=(poz+1)*sq;++i) amax(d[poz],v[i]);
}
int solve(int a,int b)
{
    int sol=0;
    if(b-a<=sqrt(n))
    {
        for(int i=a;i<=b;++i) amax(sol,v[i]);
        return sol;
    }
    int sq=sqrt(n);
    if((a-1)%sq)
    {
        int t=a/sq-(a%sq==0);
        for(int i=a;i<=(t+1)*sq;++i) amax(sol,v[i]);
        a=t*sq+1;
    }
    if(b!=n&&b%sq)
    {
        int t=b/sq;
        for(int i=t*sq;i<=b;++i) amax(sol,v[i]);
        b=t*sq-1;
    }
    if(a>b) return sol;
    a=a/sq;
    for(int i=a;i<=b;++i) amax(sol,d[i]);
    return sol;
}
int main()
{
    ios::sync_with_stdio(false);
    f>>n>>t;
    for(int i=1;i<=n;++i) f>>v[i];
    if((int)sqrt(n)*(int)sqrt(n)!=n) n=(int)sqrt(n)*(int)sqrt(n)+(int)sqrt(n);
    precalc();
    while(t--)
    {
        f>>caz>>a>>b;
        if(caz==0) g<<solve(a,b)<<'\n';
        else change(a,b);
    }
    return 0;
}