#include<fstream>
using namespace std;
int main()
{
	int k,n,i,x;
	ifstream f ("factorial.in");
	ofstream g("factorial.out");
	f>>k;
	if(k==0)
		g<<1;
	else
	{
	n=5;
	i=1;
	while (i<k)
	{
		n=n+5;
		x=n;
		while (x!=0)
		{
			if (x%5==0)
				i++;
			x=x/5;
		}
	}
	g<<n;
	}
}