// 
// Created by HJYL on 2019/9/4.
//
#include <algorithm>
#include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>
#include <set>
#include<math.h>
#include<map>
using namespace std;
const int maxn=1e6+7;
int input[maxn];

struct Node{
    int left;
    int right;
    int maxx;
}tree[maxn*4];

void pushup(int root)
{
    tree[root].maxx=max(tree[root<<1].maxx,tree[root<<1|1].maxx);
}

void build(int root,int l,int r)
{
    tree[root].left=l;
    tree[root].right=r;
    if(l==r)
    {
        tree[root].maxx=input[l];
        return;
    }
    int mid=(l+r)>>1;
    build(root<<1,l,mid);
    build(root<<1|1,mid+1,r);
    pushup(root);
}
int maxxx;
void change(int root,int dis,int k)
{
    if(tree[root].left==tree[root].right)
    {
        tree[root].maxx=k;
        return;
    }
    if(tree[root<<1].right>=dis)
        change(root<<1,dis,k);
    else
        change(root<<1|1,dis,k);
    pushup(root);
}

int search(int root,int l,int r)
{
    int maxxx=0;
    if(l<=tree[root].left&&tree[root].right<=r)
    {
        return tree[root].maxx;
    }
    if(l<=tree[root<<1].right)
        maxxx=max(maxxx,search(root<<1,l,r));
    if(r>=tree[root<<1|1].left)
        maxxx=max(maxxx,search(root<<1|1,l,r));
    return maxxx;
}

int main()
{
    int n,m;
    while(~scanf("%d%d",&n,&m)) {
        for (int i = 1; i <= n; i++)
            scanf("%d", &input[i]);
        build(1, 1, n);
        char ch[10];
        // cout<<"m="<<m<<endl;
        while (m--) {
            scanf("%s", ch);
            //getchar();
            if (ch[0] == ‘Q‘) {
                int ll, rr;
                // cout<<"hhh"<<endl;
                scanf("%d%d", &ll, &rr);
                printf("%d\n", search(1, ll, rr));
            } else {
                int p, q;
                scanf("%d%d", &p, &q);
                change(1, p, q);
            }
        }
    }
    return 0;
}