const v1 : array[1..9] of byte=(1,5,2,8,3,9,2,8,7);
      v2 : array[1..9] of byte=(1,7,0,6,1,7,8,2,1);
var n,nr,p,i,j,k : longint;
    f,g : text;
    t : integer;
    c : char;
    c1,c2 : byte;
begin
assign(f,'cifra.in'); reset(f);
assign(g,'cifra.out'); rewrite(g);
readln(f,t);
for k:=1 to t do Begin
repeat
read(f,c);
c2:=c1;
c1:=ord(c)-48;
until eoln(f);
readln(f);
n:= c2*7;
if c2 mod 2=0 then n:=n+v1[c1]
              else n:=n+v2[c1];

writeln(g,n mod 10);
n:=0; c1:=0;c2:=0;
                 End;

close(g);
end.