#include<bits/stdc++.h>
using namespace std;
int main() {
  long long N, white, ans; cin >> N;
  vector<long long> V(N);
  char c;
  cin >> c; if (c=='.') V[0]=1;
  for (long long i=1; i<N; i++) {
    cin >> c;
    if (c=='.') V[i]= V[i-1]+1;
    else V[i]= V[i-1];
  }
  white = V[N-1];
  ans = white;
  for (long long i=0; i<N; i++) {
    ans = min(ans, i+1-V[i]+ white-V[i]);
  }
  cout << ans << "\n";
}