program cifre;
const u2:array[0..1]of byte = (4,6);
      u3:array[0..1]of byte = (7,3);
      u7:array[0..1]of byte = (3,7);
      u8:array[0..1]of byte = (6,4);
var n,i,z:byte;
    t,j:word;
    f,g:text;
    m:0..1;
    l:string[101];
    s:word;
begin
 assign(f,'cifra.in');reset(f);assign(g,'cifra.out');rewrite(g);
 readln(f,t);
 for j:=1 to t do
  begin
   readln(f,l);
   val(copy(l,length(l),1),n,s);
   val(copy(l,length(l)-1,1),z,s);
   m:=z and 1;
   s:=(z*7)mod 10;
   for i:=1 to n do
     case i mod 10 of
      1,5,6,9:inc(s,i mod 10);
      4:inc(s,6);
      2:inc(s,u2[m]);
      3:inc(s,u3[m]);
      7:inc(s,u7[m]);
      8:inc(s,u8[m]);
     end;
   writeln(g,s mod 10);
  end;
 close(f);close(g);
end.