#include <bits/stdc++.h>
int main() {
  int n, i, j, wsum = 0, bsum;
  scanf("%d", &n);
  char u[n];
  for (i = 0; i < n; i++) scanf("%s", &u[i]);
  for (i = 0; i < n; i++)
    if (u[i] == '#') break;
  for (j = i + 1; j < n; j++)
    if (u[j] == '.') bsum++;
  for (i = n - 1; i >= 0; i--)
    if (u[i] == '.') break;
  for (j = i - 1; j > 0; j--)
    if (u[j] == '#') wsum++;
  if (wsum < bsum)
    printf("%d", wsum);
  else
    printf("%d", bsum);
  return 0;
}
