#include<stdio.h>

int main(void){
 	
  int N;
  long sum = 0;
  
  scanf("%d",&N);
  
  for(int i = 1;i <= N;i ++){
    if(i % 3 != 0 || i % 5 != 0){
     	sum += i; 
    }
  }
  
  printf("%ld",sum);
  
  return 0;
}
