#include <bits/stdc++.h>
using namespace std;
ifstream in("fact.in");
ofstream out("fact.out");
int p,n,d,c;
int main() {
	in>>p;
	for(n=1;;n++)
	{
		int x=n;
		while(x%2==0)
		{
			x/=2;
			d++;
		}
		while(x%5==0)
		{
			x/=5;
			c++;
		}
		if(min(d,c)==p){
			out<<n;
			return 0;
		}
		else if(min(d,c)>p){
			out<<-1;
			return 0;
		}
	}
	return 0;
}