1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cmath>
 5 #include <algorithm>
 6 #include <vector>
 7 #include <queue>
 8 #include <stack>
 9 #include <map>
10 #include <string>
11 #include <set>
12 using namespace std;
13 typedef long long LL;
14 const double EPS = 1e-8;
15 const int INF = 2e9;
16 const LL LNF = 2e18;
17 const int MAXN = 2e5+10;
18
19 int maxv[MAXN*4];
20
21 void push_up(int u)
22 {
23     maxv[u] = max(maxv[u*2], maxv[u*2+1]);
24 }
25
26 void add(int u, int l, int r, int pos, int val)
27 {
28     if(l==r)
29     {
30         maxv[u] = val;
31         return;
32     }
33
34     int mid = (l+r)/2;
35     if(pos<=mid) add(u*2, l, mid, pos, val);
36     else add(u*2+1, mid+1, r, pos, val);
37     push_up(u);
38 }
39
40 int query(int u, int l, int r, int x, int y)
41 {
42     if(x<=l && r<=y)
43         return maxv[u];
44
45     int ret = -INF;
46     int mid = (l+r)/2;
47     if(x<=mid) ret = max(ret, query(u*2, l, mid, x, y) );
48     if(y>=mid+1) ret = max(ret, query(u*2+1, mid+1, r, x, y) );
49     return ret;
50 }
51
52 int main()
53 {
54     int n, m;
55     while(scanf("%d%d", &n, &m)!=EOF)
56     {
57         memset(maxv, 0, sizeof(maxv));
58         char op[2]; int a, b;
59         for(int i = 1; i<=n; i++)
60         {
61             scanf("%d", &a);
62             add(1, 1, n, i, a);
63         }
64
65         for(int i = 1; i<=m; i++)
66         {
67             scanf("%s%d%d", op, &a, &b);
68             if(op[0]=='U') add(1, 1, n, a, b);
69             else printf("%d\n", query(1, 1, n, a, b));
70         }
71     }
72 }