#include <bits/stdc++.h>
#define left_son(x) (x << 1)
#define right_son(x) ((x << 1) + 1)

using namespace std;

const int N = 100005;

int aint[N * 4];
int n, m, start, finish, rez;
int op;

void update(int nod, int left, int right, int poz, int x)
{
    if (left == right)
    {
        aint[nod] = x;
        return;
    }
    int mid = (left + right) >> 1;
    if (poz <= mid)  update(left_son(nod), left, mid, poz, x);
    else update(right_son(nod), mid + 1, right, poz, x);
    aint[nod] = max(aint[left_son(nod)], aint[right_son(nod)]);
}

void querry(int nod, int left, int right)
{
    if (left >= start && right <= finish)
    {
        rez = max(rez, aint[nod]);
        return;
    }
    int mid = (left + right) >> 1;
    if (start <= mid) querry(left_son(nod), left, mid);
    else if (finish > mid) querry(right_son(nod), mid + 1, right);
}

int main()
{
    freopen("arbint.in", "r", stdin);
    freopen("arbint.out", "w", stdout);
    scanf("%d %d", &n, &m);
    for (int i = 1, x; i <= n; i++)
        scanf("%d", &x),
        update(1, 1, n, i, x);
    for (int i = 1; i <= m; i++)
    {
        scanf("%d %d %d", &op, &start, &finish);
        if (!op)
        {
            rez = -1;
            querry(1, 1, n);
            printf("%d\n", rez);
            continue;
        }
        else update(1, 1, n, start, finish);
    }
}