#include <bits/stdc++.h>
using namespace std;
inline int in() {
  int x;
  scanf("%d", &x);
  return x;
}
template <typename T>
inline istream& operator>>(istream& i, vector<T>& v) {
  for (int j = 0; j < ((int)(v).size()); ++j) i >> v[j];
  return i;
}
template <typename T>
string join(const vector<T>& v) {
  stringstream s;
  for (int i = 0; i < ((int)(v).size()); ++i) s << ' ' << v[i];
  return s.str().substr(1);
}
template <typename T>
inline ostream& operator<<(ostream& o, const vector<T>& v) {
  if ((int)(v).size()) o << join(v);
  return o;
}
template <typename T1, typename T2>
inline istream& operator>>(istream& i, pair<T1, T2>& v) {
  return i >> v.first >> v.second;
}
template <typename T1, typename T2>
inline ostream& operator<<(ostream& o, const pair<T1, T2>& v) {
  return o << v.first << "," << v.second;
}
template <typename T>
inline long long int suma(const vector<T>& a) {
  long long int res(0);
  for (auto&& x : a) res += x;
  return res;
}
const double eps = 1e-10;
const long long int LINF = 1001002003004005006ll;
const int INF = 1001001001;
const int MX = 200005;
int main() {
  int n;
  cin >> n;
  string s;
  cin >> s;
  long long int ans = 9999999999;
  int a = 0;
  int b = 0;
  int c = 0;
  int flag = 0;
  for (int i = 0; i < (n); ++i) {
    if (s[i] == '.') {
      a++;
      if (flag == 1) {
        c++;
      }
    } else {
      b++;
    }
    if (s[i] == '#') {
      flag = 1;
    }
  }
  flag = 0;
  int d = 0;
  for (int i = (n)-1; i >= 0; --i) {
    if (s[i] == '.') {
      flag = 1;
    } else {
      if (flag == 1) {
        d++;
      }
    }
  }
  ans = min(c, d);
  cout << ans << endl;
  return 0;
}
