1 #include <cstdio>
 2 #include <algorithm>
 3 using namespace std;
 4 
 5 struct Node{
 6     int l, r, val;
 7 };
 8 Node node[200005<<2];
 9 
10 void build(int v, int l, int r)
11 {
12     node[v].l = l;
13     node[v].r = r;
14     if(node[v].l == node[v].r){
15         scanf("%d", &node[v].val);
16         return;
17     }
18     int mid = (l+r)>>1;
19     build(v<<1, l, mid);
20     build(v<<1|1, mid+1, r);
21     node[v].val = max(node[v<<1].val, node[v<<1|1].val);
22 }
23 
24 int query(int v, int l, int r)
25 {
26     if(node[v].l == l && node[v].r == r)
27         return node[v].val;
28     int mid = (node[v].l+node[v].r)>>1;
29     if(r <= mid)
30         return query(v<<1, l, r);
31     else if(l > mid)
32         return query(v<<1|1, l, r);
33     else
34         return max(query(v<<1, l, mid), query(v<<1|1, mid+1, r));
35 }
36 
37 void update(int v, int l, int r, int m)
38 {
39     if(node[v].l == l && node[v].r == r){
40         node[v].val = m;
41         return;
42     }
43     int mid = (node[v].l+node[v].r)>>1;
44     if(r <= mid)
45         update(v<<1, l, r, m);
46     else if(l > mid)
47         update(v<<1|1, l, r, m);
48     else{
49         update(v<<1, l, mid, m);
50         update(v<<1|1, mid+1, r, m);
51     }
52     node[v].val = max(node[v<<1].val, node[v<<1|1].val);
53 }
54 
55 int main()
56 {
57     int N, M;
58     while(~scanf("%d%d", &N, &M)){
59         build(1, 1, N);
60         char order[5];
61         int A, B;
62         while(M--){
63             scanf("%s%d%d", order, &A, &B);
64             if(order[0] == ‘Q‘)
65                 printf("%d\n", query(1, A, B));
66             else
67                 update(1, A, A, B);
68         }
69     }
70     return 0;
71 }