#include<iostream>
#include<cstring>
#include<cstdio>
#include<vector>
#include<queue>
#include<stack>
#include<algorithm>
using namespace std;

inline int read(){
	int x=0,f=1;char c=getchar();
	for(;!isdigit(c);c=getchar()) if(c==‘-‘) f=-1;
	for(;isdigit(c);c=getchar()) x=x*10+c-‘0‘;
	return x*f;
}
const int MAXN=100001;
const int INF=999999;
int N,M;
int tr[800001];
int a[200001];
int A,B;

void build(int l,int r,int rt){
	if(l==r){
		tr[rt]=a[l];
		return ;
	}
	int mid=(l+r)>>1;
	build(l,mid,rt*2);
	build(mid+1,r,rt*2+1);
	tr[rt]=max(tr[rt*2],tr[rt*2+1]);
	return ;
}
void Upd(int l,int r,int rt,int k,int x){
    if(l==r){
    	tr[rt]=x;
    	return ;
	}
	int mid=(l+r)>>1;
	if(k<=mid) Upd(l,mid,rt*2,k,x);
	else Upd(mid+1,r,rt*2+1,k,x);
	tr[rt]=max(tr[rt*2],tr[rt*2+1]);
	return ;
}
int Que(int l,int r,int rt,int L,int R){
	if(l>=L&&r<=R){
		return tr[rt];
	}
	int mid=(l+r)>>1,ans=0;
	if(R>mid) ans=max(ans,Que(mid+1,r,rt*2+1,L,R));
	if(L<=mid) ans=max(ans,Que(l,mid,rt*2,L,R));
	return ans;
}
 
int main(){
	while(scanf("%d%d",&N,&M)!=EOF){
		memset(tr,0,sizeof(tr));
		for(int i=1;i<=N;i++) a[i]=read();
		build(1,N,1);
		while(M--){
			char c;cin>>c;
			A=read(),B=read();
			if(c==‘Q‘) printf("%d\n",Que(1,N,1,A,B));
			else Upd(1,N,1,A,B);
		}
	} 
}