1 #include "bits/stdc++.h"
 2 #define lson rt<<1,l,m
 3 #define rson rt<<1|1,m+1,r
 4 using namespace std;
 5 typedef long long LL;
 6 const int MAX=200005;
 7 int n,m;
 8 int c[MAX*4];
 9 inline int mx(int x,int y){return x>y?x:y;}
10 void PushUp(int rt){
11     c[rt]=mx(c[rt<<1],c[rt<<1|1]);
12 }
13 void build(int rt,int l,int r){
14     if (l==r){
15         scanf("%d",&c[rt]);
16         return;
17     }
18     int m=(l+r)>>1;
19     build(lson);
20     build(rson);
21     PushUp(rt);
22 }
23 void update(int rt,int l,int r,int x,int y){
24     if (l==r && l==x){
25         c[rt]=y;
26         return;
27     }
28     int m=(l+r)>>1;
29     if (m>=x)
30      update(lson,x,y);
31     else
32      update(rson,x,y);
33     PushUp(rt);
34 }
35 int search(int rt,int l,int r,int x,int y){
36     if (x<=l && y>=r)
37      return c[rt];
38     int an(0),m=(l+r)>>1;
39     if (x<=m)
40      an=max(an,search(lson,x,y));
41     if (y>m)
42      an=max(an,search(rson,x,y));
43     return an;
44 }
45 int main(){
46     freopen ("hate.in","r",stdin);
47     freopen ("hate.out","w",stdout);
48     int i,j;char c;int x,y;
49     while (~scanf("%d%d",&n,&m)){
50         build(1,1,n);
51         for (i=1;i<=m;i++){
52             c=getchar();
53             scanf("%c%d%d",&c,&x,&y);
54             if (c==‘Q‘)
55              printf("%d\n",search(1,1,n,x,y));
56             else 
57              update(1,1,n,x,y);
58         }
59     }
60     return 0;
61 }