program cifra;
var f,g:text;
    a,v:array[1..10000]of longint;
    t,y,n,ok,p,c,r,k,i,s:longint;
    x:char;
begin
assign(f,'cifra.in');
assign(g,'cifra.out');
reset(f);
rewrite(g);
readln(f,t);
for y:=1 to t do
  begin
    n:=0;
    while not eoln(f) do
      begin
        inc(n);
        read(f,x);
        v[n]:=ord(x)-ord('0');
      end;
    readln(f);
    ok:=0;
    if (n=1)then ok:=1 else
    if (n=2)and(v[1]<2)then ok:=1 else
    if (n=2)and(v[1]=2)and(v[2]=0)then ok:=1;
    if (ok=0)then
      begin
        if (v[1]*10+v[2]>=20)then
          begin
            p:=v[1]*10+v[2];
            c:=2;
          end else
          begin
            p:=v[1]*100+(v[2]*10)+v[3];
            c:=3;
          end;
        while (c<=n)do
          begin
            k:=p div 20;
            r:=p mod 20;
            inc(c);
            p:=r*10+v[c];
          end;
      end else
      begin
        if (n=1)then r:=v[1] else
        r:=v[1]*10+v[2];
      end;
    n:=r;
    if (n=1)then s:=1 else
    if (n=2)then s:=5 else
    if (n=3)then s:=2 else
    if (n=4)then s:=8 else
    if (n=5)then s:=3 else
    if (n=6)then s:=9 else
    if (n=7)then s:=2 else
    if (n=8)then s:=8 else
    if (n=9)then s:=7 else
    if (n=10)then s:=7 else
    if (n=11)then s:=8 else
    if (n=12)then s:=4 else
    if (n=13)then s:=7 else
    if (n=14)then s:=3 else
    if (n=15)then s:=8 else
    if (n=16)then s:=4 else
    if (n=17)then s:=1 else
    if (n=18)then s:=5 else
    if (n=19)then s:=4 else
    if (n=20)then s:=4;
    if (ok=0)then writeln(g,(4*k+s)mod 10) else writeln(g,s);
  end;
close(f);
close(g);
end.