#include <stdio.h>

long long int a[15] = {0, 0, 0, 2, 2, 4, 6, 6, 6, 8, 10, 10, 12, 12, 12};

int main(void) {
	long long int n;
	scanf("%lld", &n);
	long long int v = (n / 15) * 16 + a[n % 15];
	printf("%lld\n", v);
	return 0;
}