#include <iostream>
#include <fstream>

using namespace std;

int p;

void solve()
{
	fstream f("fact.in", ios::in);
	fstream g("fact.out", ios::out);
	f>>p;
	if (p==0)
		g<<"1\n";
	else
	{
		int nr=0;
		int i;
		for (i=5; nr+1!=p; i+=5)
		{
			int aux=i;
			while (aux%5==0)
			{
				++nr;
				aux=aux/5;
			}
		}
		g<<i;
	}
	g.close();	
}

int main()
{
	solve();
	return 0;
}