#include <fstream.h>
#include <iostream.h>
int main()
{
   ifstream fin("factorial.in");
   ofstream fout("factorial.out");
   int n=0,b,ct=0,p;
   fin>>p;
   while (ct<p)
   {
    n=n+5;
    b=n;
    while (b%5==0)
    {
     b=b/5;
     ct=ct+1;
    }
   }
   if (p==0) n=1;
   fout<<n;
   return 0;
}