/// The Towers Of Hanoi
/// Yacas Implementation
/// Copyright (C) 2002 Amit Singh. All Rights Reserved.
/// http://hanoi.kernelthread.com
///
/// Last tested under Yacas 1.0.54
///
/// Usage: At the yacas input prompt, type the following commands:
///
///     Use("hanoi.ys")
///     hanoi(3)
///
/// YACAS (Yet Another Computer Algebra System)
/// http://yacas.sourceforge.net
///

10 # H(_n, _f, _u, _t) _ (n = 1) <-- Echo(f, " --> ", t);
20 # H(n_IsInteger, f_IsInteger, u_IsInteger, t_IsInteger) _ (n > 1) <-- [
    H(n - 1, f, t, u);
    Echo(f, " --> ", t);
    H(n - 1, u, f, t);
];

10 # hanoi(_n) _ (n < 1) <-- [
    Echo("the number of disks must be a positive integer");
    False;
];

20 # hanoi(_n) _ (n > 10) <-- [
    Echo("the number of disks must be less than or equal to 10");
    False;
];

30 # hanoi(n_IsInteger)  <-- H(n, 1, 2, 3);