#include <bits/stdc++.h>
using namespace std;
const int inf = 1e9 + 7;
const long long longinf = 1LL << 60;
const int mx = 100010;
const long long mod = 1e9 + 7;
int main() {
  int n;
  cin >> n;
  string s;
  cin >> s;
  int ans = 0;
  bool flag = false;
  for (int i = (int)(0); i < (int)(n); ++i) {
    if (flag && s[i] == '.') {
      ans++;
      continue;
    }
    if (s[i] == '#') flag = true;
  }
  cout << ans << endl;
  return 0;
}
