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

int main()
{
	int fact;
	int countFives=0;
	int i;
	int k;
	ifstream in("fact.in");
	ofstream out("fact.out");
	in>>fact;
	if(fact==0)
	{
		out<<1;
	}
	else
	{
		for(i=5,countFives=0; countFives<fact; i+=5)
		{
			k=i;
			while((k%5)==0)
			{
				++countFives;
				k=k/5;
			}
		}
		i-=5;
		out<<i;
	}
	return 0;
}