#include<stdio.h>

int main()
{
	int N,i1,i2,a=0,e=0;
	
	
	
	
	scanf("%d",&N);
	
	i1=N/3*2;
	i2=N/5*2;
	a=i1+i2;
	
	
	printf("%d\n",a);
	
	
	
	return 0;
}