var v:array[1..100] of 0..9;
s:array[0..19] of 0..9;
t,n,i,m,j,a,r:longint;
c:char;
f,g:text;
begin
s[0]:=0;s[1]:=1;s[2]:=5;s[3]:=2;s[4]:=8;s[5]:=3;s[6]:=9;s[7]:=2;s[8]:=8;
s[9]:=7;s[10]:=7;s[11]:=8;s[12]:=4;s[13]:=7;s[14]:=3;s[15]:=8;s[16]:=4;
s[17]:=1;s[18]:=5;s[19]:=4;
assign(f,'cifra.in');
assign(g,'cifra.out');
reset(f);rewrite(g);
readln(f,t);
for i:=1 to t do
    begin
    m:=0;
    repeat
          m:=m+1;
          read(f,c);
          v[m]:=ord(c)-48;
    until eoln(f);
    readln(f);
    r:=0;
    a:=0;
    for j:=1 to m-1 do
        begin
        a:=(r*10+v[j]) div 2;
        r:=v[j] mod 2;
        end;
    writeln(g,(4*a mod 10+s[r*10+v[m]]) mod 10);
    end;
close(f);close(g);
end.