#include <fstream>
using namespace std;

ifstream in("fact.in");
ofstream out("fact.out");

long i,s,n;

void breakdiv(long x)
{
while(!(x%5))
	{s++;x/=5;}
}

int main()
{
in>>n;
if(!n)
	{
	out<<1;
	return 0;
	}
else
	{
	for(i=5; s<n; i+=5)
		breakdiv(i);
	i-=5;
	
	out<<i;
	}
	
return 0;
}