#include<fstream>
using namespace std;
ifstream fin("fact.in");
ofstream fout("fact.out");
int main()

{
    int p,x=0,y,k=0;
	long i=5;
	fin>>p;
	if(p==0)fout<<"1";
	while(k<p)
	{
		y=x;
		while(y%5==0)
		{
			y=y/5;
			k++;
		}
		x=x+5;
	}
	fout<<x;
	fin.close();
	fout.close();
	return 0;
}