#include<cstdio>#include<cstring>#include<iostream>#include<algorithm>using namespace std;int sum[1000000];void push(int rt){    sum[rt]=max(sum[rt<<1],sum[rt<<1|1]);}void build(int l,int r,int rt){    if(l==r){scanf("%d",&sum[rt]);return ;}    int m=(l+r)>>1;    build(l,m,rt<<1);build(m+1,r,rt<<1|1);    push(rt);}void update(int key,int neww,int l,int r,int rt){    if(l==r){ sum[rt]=neww; return ;}    int m=(l+r)>>1;    if(key<=m) update(key,neww,l,m,rt<<1);    else update(key,neww,m+1,r,rt<<1|1);    push(rt);}int query(int L,int R,int l,int r,int rt){    if(L<=l&&r<=R) {return sum[rt];}    int m=(l+r)>>1;    int ret1=-1,ret2=-1;    if(L<=m) ret1=query(L,R,l,m,rt<<1);    if(R>m)  ret2=query(L,R,m+1,r,rt<<1|1);    return max(ret1,ret2);}int main(){    int n,m;    int i,j,k;    int l,r;    char que[10];    while(scanf("%d%d",&n,&m)!=EOF)    {        build(1,n,1);        while(m--)        {            scanf("%s%d%d",&que,&l,&r);            if(que[0]==‘U‘)            {                update(l,r,1,n,1);            }            else            {                printf("%d\n",query(l,r,1,n,1));            }        }    }    return 0;}