#include <stdio.h>#define MAXN 800002int arr[MAXN];void build(int left,int right,int root){int mid;if(left==right){scanf("%d",&arr[root]);return;}mid=(left+right)>>1;build(left,mid,root<<1);build(mid+1,right,root<<1|1);arr[root]=arr[root<<1]>arr[root<<1|1]?arr[root<<1]:arr[root<<1|1];}void update(int x,int val,int left,int right,int root){int mid;if(left==right){arr[root]=val;return;}mid=(left+right)>>1;if(x<=mid)update(x,val,left,mid,root<<1);elseupdate(x,val,mid+1,right,root<<1|1);arr[root]=arr[root<<1]>arr[root<<1|1]?arr[root<<1]:arr[root<<1|1];}int query(int st,int end,int left,int right,int root) { int mid,ret=0,lx=0,rx=0; if(st<=left&&end>=right) return arr[root]; mid=(left+right)>>1; if(st<=mid) lx=query(st,end,left,mid,root<<1);if(end>mid) rx=query(st,end,mid+1,right,root<<1|1);ret=lx>rx?lx:rx;return ret; } int main(){int n,m,x,y;char cmd[3];while(scanf("%d %d",&n,&m)!=EOF){build(1,n,1);while(m--){scanf("%s %d %d",cmd,&x,&y);if(cmd[0]=='Q')printf("%d\n",query(x,y,1,n,1));elseupdate(x,y,1,n,1);}}return 0;}
