#include <bits/stdc++.h>
int main() {
  int i, j, a = 0, b = 0, N;
  scanf("%d", &N);
  char stone[N], hozon[N];
  scanf("%s", stone);
  for (i = 0; stone[i] != '\0'; i++) {
    hozon[i] = stone[i];
  }
  for (i = 0; stone[i] != '\0'; i++) {
    if (stone[i] == '#' && stone[i + 1] == '.') {
      for (j = i; stone[j] != '\0'; j++) {
        a++;
        if (stone[j + 1] == '.') {
          b++;
          break;
        }
      }
    }
  }
  for (i = 0; stone[i] != '\0'; i++) {
    stone[i] = hozon[i];
  }
  for (i = N; i >= 0; i--) {
    if (stone[i] == '.' && stone[i - 1] == '#') {
      for (j = i; j >= 0; j--) {
        b++;
        if (stone[j - 1] == '#') {
          b++;
          break;
        }
      }
    }
  }
  if (a < b) {
    printf("%d", a);
  } else {
    printf("%d", b);
  }
}
