1 #include <iostream>
2 #include <stdlib.h>
3 #include <string.h>
4 #include <vector>
5 #include <algorithm>
6
7 using namespace std;
8 bool CmpInt_1(int a,int b)
9 {
10 return a<b;
11 }
12
13 int main()
14 {
15 int n;
16 int i;
17 cin >> n;
18
19 vector<int> ATtotal(n+10,0);
20 int ATtotal_end = 0;
21 int tmp_cnt = 0;
22 int ATnum = 0;
23 int CGnum = 0;
24 char tmp_inputchar;
25 for(i = 0;i < n;i ++)
26 {
27 cin >> tmp_inputchar;
28
29 if(tmp_inputchar=='A'||tmp_inputchar=='T')
30 {
31 tmp_cnt ++;
32 ATnum ++;
33 }
34 else if(tmp_inputchar=='C'||tmp_inputchar=='G')
35 {
36 ATtotal[ATtotal_end++] = tmp_cnt;
37 tmp_cnt = 0;
38 CGnum ++;
39 }
40 }
41
42 ATtotal[ATtotal_end++] = tmp_cnt;
43 sort(ATtotal.begin(),ATtotal.end(),CmpInt_1);
44
45 int result = 0;
46 for(i = ATtotal.size()-1; i >=0; i --)
47 {
48 if(CGnum>=ATnum)
49 {
50 break;
51 }
52 else
53 {
54 CGnum += ATtotal[i];
55 ATnum -= ATtotal[i];
56 result ++;
57 }
58 }
59 cout << result << endl;
60
61 return 0;
62 }
