#include <fstream>
using namespace std;

int cifra(unsigned long a,unsigned long b)
{
   int r,c,p=1;
   if(a%10==0||a%10==1||a%10==5||a%10==6)
       return a%10;
   r=b%4;
   if(r==0)  r=4;
   c=a%10;
   while(r)
   { p=p*c;
     r--;
   }
   return p%10;
}
int main()
{  ifstream f("cifra.in");
   ofstream g("cifra.out");
   int s;
   unsigned long x,i;
   f>>x;
   while(f>>x)
   {  s=0;
       for(i=1;i<=x;++i)
          s=s+cifra(i,i);
      g<<s%10<<"\n";
   }
   f.close();
   g.close();
   return 0;
}