#include<fstream>
using namespace std;
ifstream f("fact.in");
ofstream g("fact.out");
int main()
{
	int x,i,s,fr=0;
	f>>x;
	if(x==0)g<<1;
	else
	{	
	for(i=5;fr<x;i+=5)
	{
		s=i;
		while(i%5==0){i=i/5;fr++;}
		i=s;
		if(fr>x){i=4;break;}
	}
	g<<i-5;
	}
}