program suma;
const fin = 'cifra.in';
      fout = 'cifra.out';
      a1:array [0..9] of byte = (0,1,5,2,8,3,9,2,8,7);
      a2:array [0..9] of byte = (0,1,7,0,6,1,7,4,8,7);
var aux,t,c:integer;
    a:array [0..100] of char;

begin
  assign(input,fin);
  assign(output,fout);
  reset(input);
  rewrite(output);
  readln(t);
  a[0]:='0';
  while not eof() do
  begin
    c:=0;
    while not eoln() do
    begin
      inc(c);
      read(a[c]);
    end;
    readln;
    aux:=ord(a[c-1])-48
    t:= 7*aux mod 10;
    if aux mod 2 = 0 then
      inc(t,a1[(ord(a[c])-48)])
    else
      inc(t,a2[(ord(a[c])-48)]);
    writeln(t mod 10);
  end;


  close(input);
  close(output);
end.