class Hanoi
{
	// this solves Problem P5.21 of the textbook.

	public static void hanoi( int fromPeg, int toPeg, int n )
	{
		int tmpPeg = 1 + 2 + 3 - fromPeg - toPeg;
		// pegs are numbered 1,2,3 ... compute our tmp peg

		if( n == 1 ) {
			System.out.print  ( "Move disk from " + fromPeg );
			System.out.println( " to " + toPeg );
		} else {
			// move n-1 disks from fromPeg to tmpPeg
			// move nth disk  from fromPeg to toPeg
			// move n-1 disks from tmpPeg back to toPeg
			hanoi( fromPeg, tmpPeg, n-1 );
			hanoi( fromPeg,  toPeg,   1 );
			hanoi(  tmpPeg,  toPeg, n-1 );
		}
	}

	public static void main( String[] args )
	{
		// move 4 disks from peg 1 to peg 2
		hanoi( 1, 2, 4 );
	}
}