#include<iostream>
#include<fstream>
using namespace std;

int s(int i)
{if(i==0) return 1;
else return (pow(5.0,double(i))+s(i-1));

}
int main()
{int p,n=0,i,j;
ifstream fin("fact.in");
fin>>p;
fin.close();
ofstream fout("fact.out");
do
{
	i=0;
	while(p>=s(i)) i++;
	j=i-1;
	n=n+pow(5.0,double(j));
	p=p-s(j);
}while(p!=0);
n=n*5;
fout<<n;

	



fout.close();
return 0;
}