#include<stdio.h>
#include<string.h>

int main(){
  unsigned long long int n;
  unsigned long long int i;
  unsigned long long int sum=0;
  scanf("%llu",&n);

  for(i=1;i<=n;i++){
    if(i%3==0 && i%5==0){sum+=4;}
    else if(i%3==0 && i%5!=0){sum+=2;}
    else if(i%3!=0 && i%5==0){sum+=2;}
    else{}
  }
  printf("%llu",sum);
}