#include <fstream>
using namespace std;

int ultimacifra(long a,long b)
{ int i,u=1;
  a=a%10;
  for(i=1;i<=b;i++)
    u=(u*a)%10;
  return u;
}
int main()
{  ifstream f("cifra.in");
   ofstream g("cifra.out");
   int s;
   long x,i;
   f>>x;
   while(f>>x)
   {  s=0;
       for(i=1;i<=x;++i)
          s=(s+ultimacifra(i,i))%10;
      g<<s<<"\n";
   }
   f.close();
   g.close();


   return 0;
}