INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A

INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A

INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
INCREASE A INCREASE A INCREASE A INCREASE A INCREASE A
# A = 179 is the length of the Maximum collatz sequence (X=871)

REPEAT A TIMES ( # Basically a WHILE TRUE
    # Check to terminate
    CLEAR B CLEAR C
    REPEAT X TIMES (
        CLEAR D INCREASE D
        REPEAT C TIMES ( CLEAR D INCREASE B )
        CLEAR C
        REPEAT D TIMES ( INCREASE C )
    )
    CLEAR D INCREASE D
    REPEAT B TIMES ( CLEAR D )
    CLEAR E INCREASE E
    REPEAT D TIMES ( CLEAR E )
    # B := HALF X
    # C := MOD2 X
    # D := ISZERO HALF X
    # E := NOT ISZERO HALF X 

    
    REPEAT E TIMES ( # If we do not terminate
        PRINT X
        REPEAT C TIMES ( # If X is odd, Multiply by 3 and add 1.
            CLEAR F
            REPEAT X TIMES ( INCREASE F )
            REPEAT X TIMES ( INCREASE F )
            REPEAT X TIMES ( INCREASE F )
            INCREASE F
            PRINT F # F = 3X+1
            REPEAT B TIMES ( INCREASE X )
            INCREASE X
        ) 

        CLEAR D INCREASE D # Otherwise it is even.
        REPEAT C TIMES ( CLEAR D )
        # D = NOT C
        REPEAT D TIMES ( # Otherwise X is even. Divide by 2.
            CLEAR X
            REPEAT B TIMES ( INCREASE X )
        )
    )
)
PRINT X