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