#include <bits/stdc++.h>
using namespace std;
int main(void) {
  int N;
  cin >> N;
  string S;
  cin >> S;
  int white_num = count(S.begin(), S.end(), '.');
  int black_num = count(S.begin(), S.end(), '#');
  int ans = 0;
  if (black_num == 0)
    ans = 0;
  else
    ans = white_num;
  cout << ans << endl;
  return 0;
}
