#include <fstream.h>
int main(){
	unsigned long p,k,i,aux;
	ifstream f("fact.in");
	ofstream g("fact.out");
	f>>p;
	if(p>0){
		if(p%6!=p){
			k=p/6;
			i=(p*5)-k*5;
			g<<i;
		}else{
			i=p*5;
			g<<i;
                }
	}else
		g<<1;
}