#include <iostream>
#include <fstream>
using namespace std;

int pow(int a, int b){
	int r=1;
	while(b>0){
		r = r * a;
		b--;
	}
	return r;
}

int main(){
	
	int P;
	
	ifstream f("fact.in");
	f>>P;
	f.close();
	
	P=P*4;
	
	bool ok=true;
	int k=2;
	
	while(ok){
		int putere = pow(5,k);
		double rez = P * putere / (putere-1);
		if(rez % 1 == 0)
			ok=false;
		else k++;
	}
	
	ofstream g("fact.out");
	g<<rez;
	g.close();
	
	return 0;
}