#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  string s;
  cin >> s;
  bool bl = false;
  int ans = 0;
  for (int i = 0; i < n; i++) {
    if (s[i] == '#') {
      bl = true;
    }
    if (bl && s[i] == '.') {
      ans++;
    }
  }
  cout << ans << endl;
  return 0;
}
