#include <iostream>
#include <string>
#include <map>
using std::cin;
using std::cout;

int correct_guess(std::string abc, std::string s) {
int s_len = s.length();
int abc_len = abc.length();
int itr = 0, cnt = 0, s_pos = 0, rem = 0;
if(s_len > abc_len) {

  itr = s_len / abc_len;
  rem = s_len % abc_len;

  while(itr-- > 0) {
    for(int i = 0; i < abc_len; i++) {
      if(s.at(s_pos) == abc.at(i)) {
        cnt++;
      }
      s_pos++;
    }

    if(itr == 0 && rem != 0) {
      for(int j = 0; j < rem; j++) {
        if(s.at(s_pos) == abc.at(j)){
        cnt++;
        }
      }
    }
  }
}
else {
  for(int i = 0; i < s_len; i++) {
    if(s.at(i) == abc.at(i)) {
      cnt++;
    }
  }
}

return cnt;
}

int main(int argc, char** argv) {
std::map<int, std::string> sorter;
int n;
std::string a = "ABC";
std::string b = "BABC";
std::string c = "CCAABB";
std::string s;

cin >> n >> s;
int a_amnt = correct_guess(a,s);

int b_amnt = correct_guess(b,s);

int c_amnt = correct_guess(c,s);


return 0;
}