include<iostream>
using namespace std;

int main(){
  int n; cin >> n;
  string s; cin >> x;
  int pnt = 0;
  for(int i = 0; i < n; ++i){
    if(s[i] == '#')pnt++;
  }
  int ans;
  for(int i = n - 1; i >= 0; --i){
    if(s[i] == '.')pnt++;
    else pnt--;
  }
  if(ans < pnt)ans = pnt;
  cout << ans << endl;
  return 0;
}