class MAIN is

  ackermann(m, n:INTI):INTI is
    zero ::= 0.inti; -- to avoid type conversion each time
    one  ::= 1.inti;
    if m = zero then return n + one; end;
    if n = zero then return ackermann(m-one, one); end;
    return ackermann(m-one, ackermann(m, n-one));
  end;

  main is
    n, m :INT;
    loop n := 0.upto!(6);
      loop m := 0.upto!(3);
        #OUT + "A(" + m + ", " + n + ") = " + ackermann(m.inti, n.inti) + "\n";
      end;
    end;
  end;
end;