#include<fstream>
using namespace std;
int n,s,p,cn;
int main(){
	ifstream in("fact.in");
	ofstream out("fact.out");
	in>>p;
	do {
		n++;
		cn=n;
		while(n%5==0){
			s++;
			n=n/5;
		}
		n=cn;
	}while(s<p);
	out<<n;
	return 0;
}