#include <stdio.h>

int main() {

  int i,j,temp,n,cnt=0;
  scanf("%d",&n);
  int data[n];
  for(i=0;i<n;i++){
    for(j=0;j<n-1-i;j++){
      if(data[j]>data[j+1]){
        temp = data[j];
        data[j] = data[j+1];
        data[j+1] = temp;
      }
    }
  }
  for(i=1;i<n-1;i++)
    if(data[i-1] != data[i] && data[i] != data[i+1])
      cnt++;

  printf("%d",cnt);
  }