1 #include <cstdio>
 2 #include <cmath>
 3 #include <cstdlib>
 4 #include <cstring>
 5 #include <queue>
 6 #include <stack>
 7 #include <vector>
 8 #include <iostream>
 9 #include "algorithm"
10 using namespace std;
11 typedef long long LL;
12 
13 #define lson rt<<1,l,m
14 #define rson rt<<1|1,m+1,r
15 
16 const int MAX=200005;
17 int n,m;
18 int Max[MAX<<2];
19 
20 void PushUp(int rt){Max[rt]=max(Max[rt<<1],Max[rt<<1|1]);}
21 
22 void build(int rt,int l,int r){
23     if (l==r)
24     {scanf("%d",&Max[rt]);
25      return;
26     }
27     int m=(l+r)>>1;
28     build(lson);
29     build(rson);
30     PushUp(rt);
31 }
32 void update(int rt,int l,int r,int x,int y){
33     if (l==r)
34     {Max[rt]=y;
35      return;
36     }
37     int m=(l+r)>>1;
38     if (x<=m)
39      update(lson,x,y);
40     else
41      update(rson,x,y);
42     PushUp(rt);
43 }
44 int query(int rt,int l,int r,int x,int y){
45     if (x<=l && r<=y)
46      return Max[rt];
47     int m=(l+r)>>1;
48     int ans(0);
49     if (x<=m)
50      ans=max(ans,query(lson,x,y));
51     if (y>m)
52      ans=max(ans,query(rson,x,y));
53     return ans;
54 }
55 int main(){
56     freopen ("hate.in","r",stdin);
57     freopen ("hate.out","w",stdout);
58     int i,j;
59     int x,y;
60     char c;
61     while (scanf("%d%d",&n,&m)!=EOF){
62     build(1,1,n);
63     while (m--)
64     {c=getchar();
65      while (!(c==‘Q‘ || c==‘U‘)) c=getchar();
66      scanf("%d%d",&x,&y);
67      if (c==‘Q‘)
68       printf("%d\n",query(1,1,n,x,y));
69      if (c==‘U‘)
70       update(1,1,n,x,y);
71     }}
72     return 0;
73 }