#include<fstream.h>
#include<math.h>

long i, p, n, s;

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

void main()
{f>>p;
while(s<p)
{for(i=0;s<=p;i++)
s=(s*5)+1;
s=(s-1)/5;
n=n+pow(5,(i-1));
p-=s;
s=0;}
g<<n;
f.close;
g.close;}