Program cifra;
Procedure cit_fis;
var t,f: text;
    n,i,j,b,a,q,suma,aux: longint;
begin
      assign(t,'cifra.in'); reset(t);
      readln(t,n);
      assign(f,'cifra.out'); rewrite(f);
      for i:=1 to n do
        begin
          readln(t,b);
          suma:=0;
           for q:=1 to b do
           begin
             aux:=q mod 10;
             a:=aux;
             for j:=2 to q do
              begin
               aux:=aux*a;
               aux:=aux mod 10;
              end;
            suma:=suma+aux;
            suma:=suma mod 10;
           end;
          writeln(f,suma);
        end;
      close(t);
      close(f);
end;
begin
   cit_fis;
end.