1 #include <iostream>
 2 #include <cstring>
 3 #include <cstdio>
 4 #include <string>
 5 #include <iomanip>
 6 #include <stdio.h>
 7 #include <algorithm>
 8 using namespace std;
 9 #define maxn 200020
10 #define lson l,m,rt<<1
11 #define rson m+1,r,rt<<1|1 
12 int cnt[maxn<<2];
13 int N, M;
14 int max(int a, int b){
15     return a>b?a:b;
16 }
17 void PushUP(int rt){
18     cnt[rt] = max( cnt[rt<<1],cnt[rt<<1|1]); 
19 }
20 void build(int l, int r, int rt){
21     if(l == r){
22         scanf("%d", &cnt[rt]);
23         return;
24     }
25     int m = (l+r)>>1;
26     build(lson);
27     build(rson);
28     PushUP(rt);
29 }
30 void update(int p, int add, int l, int r, int rt){
31     if(l == r){
32         cnt[rt] = add;
33         return;
34     }
35     int m = (l+r)>>1;
36     if(p <= m) update(p, add, lson);
37     else update(p, add, rson);
38     PushUP(rt);
39 }
40 int query(int L, int R, int l, int r, int rt){
41     if(L <= l && r <= R){
42         return cnt[rt];
43     }
44     int m = (l+r)>>1;
45     int ret = 0;
46     if(L <= m) ret = max(ret,query(L, R, lson));
47     if(R > m) ret = max(ret, query(L, R, rson));
48     return ret;
49 }
50 int main(){
51     while(~scanf("%d%d", &N, &M)){
52         build(1, N, 1);
53         while(M--){
54             char c[2];
55             scanf("%s", &c);
56             int a, b; 
57             scanf("%d%d", &a, &b);
58             if(c[0] == ‘Q‘) printf("%d\n", query(a, b, 1, N, 1));
59             else if(c[0] == ‘U‘) update(a, b, 1, N, 1);
60         }
61     }
62     return 0;
63 }