#include <fstream>
using namespace std;

ifstream is ("fact.in");
ofstream os ("fact.out");

int main()
{
       int n, p,k = -1;
       is >> p;

       for (int i = 0; i < 100000000; i+= 5)
       {

              ++k;
              if (p == 0)
              {
                     os << 1; break;
              }
              else
                     if ( p == k  )
                     {
                            os << i; break;
                     }





       }



       os.close();
       is.close();
       return 0;
}