#include<iostream>
#include<fstream>
#include<math.h>
using namespace std;
ifstream in("fact.in");
ofstream out("fact.out");

int p,n=0,d=0,c=0;

int main()
{
	int aux,i;
	in>>p;
	for(i=1;c<p; i++)
	{
		aux=i;
		while((aux%5==0 || aux%2==0)&& aux>1)
		{
			if(aux%5==0)
			{
				c++;
				aux/=5;
			}
			if(aux%2==0)
			{
				d++;
				aux/=2;
			}
		}		
	}
	if(p==0)
	{i=2;}
	out<<(i-1);
	out.close();
	return 0;
	
}