#include<fstream>
using namespace std;
ifstream f("fact.in");
ofstream g("fact.out");
int p,n=1,a,nr,c,z=1;
long b;
int main()
{ f>>p;
  if(p>=10) n=(p-1)*5;
  else n=p*5;
  if(p==0) g<<"1";
  else g<<n;
}