#include<iostream>
#include<stdio.h>
#include<algorithm>
#include<math.h>
#define max1 2000005
int a[max1];
using namespace std;
const int INFINITE=-1111111;
struct SegTreeNode
{
    int val;
    int addMark;
}segTree[max1<<1];
void build(int root,int arr[],int istart,int iend)
{
    segTree[root].addMark=0;
    if(istart==iend)
        segTree[root].val=arr[istart];
    else
    {
        int mid=(istart+iend)/2;
        build(root*2+1,arr,istart,mid);
        build(root*2+2,arr,mid+1,iend);
        segTree[root].val=max(segTree[root*2+1].val,segTree[root*2+2].val);
    }
}
/*void pushDown(int root)
{
    if(segTree[root].addMark!=0)
    {
        segTree[root*2+1].addMark+=segTree[root].addMark;
        segTree[root*2+2].addMark+=segTree[root].addMark;
        segTree[root*2+1].val+=segTree[root].addMark;
        segTree[root*2+2].val+=segTree[root].addMark;
        segTree[root].addMark=0;
    }

}*/
int query(int root,int nstart,int nend,int qstart,int qend)
{
    if(qstart>nend||qend<nstart)
        return INFINITE;
    if(qstart<=nstart&&qend>=nend)
        return segTree[root].val;
   // pushDown(root);
    int mid = (nstart+nend)/2;
    return max(query(root*2+1,nstart,mid,qstart,qend),query(root*2+2,mid+1,nend,qstart,qend));
}
/*void update(int root,int nstart,int nend,int ustart,int uend,int addVal)
{
    if(ustart>nend||uend<nstart)
        return;
    if(ustart<=nstart&&uend>=nend)
    {
        segTree[root].addMark+=addVal;
        segTree[root].val+=addVal;
        return;
    }
    //pushDown(root);
    int mid=(nstart+nend)/2;
    update(root*2+1,nstart,mid,ustart,uend,addVal);
    update(root*2+2,mid+1,nend,ustart,uend,addVal);
    segTree[root].val=max(segTree[root*2+1].val,segTree[root*2+2].val);
}*/
void updateOne(int root,int nstart,int nend,int index,int addVal)
{
    if(nstart==nend)
    {
        if(index==nstart)
            segTree[root].val=addVal;
        return;
    }
    int mid=(nstart+nend)/2;
    if(index<=mid)
        updateOne(root*2+1,nstart,mid,index,addVal);
    else
        updateOne(root*2+2,mid+1,nend,index,addVal);
    segTree[root].val=max(segTree[root*2+1].val,segTree[root*2+2].val);
}
int main()
{
    int n,m;
    while(~scanf("%d%d",&n,&m)){

        for(int i=0;i<n;i++)
            scanf("%d",&a[i]);getchar();
        build(0,a,0,n-1);
        //for(int i=0;i<2*n-1;i++)
        //    cout<<segTree[i].val<<endl;

        char mov;
        int p1;
        int p2;
        for(int i=0;i<m;i++)
        {
            scanf("%c",&mov);
            scanf("%d%d",&p1,&p2);
            getchar();
            if(mov==‘U‘)
            {
                updateOne(0,0,n-1,p1-1,p2);
            }
            if(mov==‘Q‘)
            {
                printf("%d\n",query(0,0,n-1,p1-1,p2-1));
            }
        }
    }
    return 0;
}