#include <stdio.h>
void main(void){
	int numList[] = {2,2,-1,-1,2,-1,-1};
	int x;
	scanf("%d",&x);
	
	int i = 0 , ans = 0 , count = 0;
	while(ans != x){
		ans += numList[i];
		if(numList[i] == -1){
			count++;
		}else{
			count += 2;
		}
		i++;
		if(i == 7){
			i = 0;
		}
	}
	printf("%d",count);
}