main :: [Int]
    = letrec eval' :: ([Int] -> [Int] -> Int -> Int -> Int -> [Int]) output mem r0 r1 ip =
			if getMem mem ip == 0 then output else evalInstruction output mem r0 r1 ip;
	     eval :: ([Int] -> [Int]) inp =
			eval' Nil inp 0 0 0;
             input :: ([Int]) =
			(Cons 3 (Cons 3 (Cons 3 (Cons 3
			(Cons 8 (Cons 0 (Cons 7 (Cons 11
			(Cons 0 (Cons 8 (Cons 0 (Cons 13
			(Cons 0 (Cons 0 (Cons 14 (Cons 0
			(Nil)))))))))))))))));
	     ding :: ([Int] -> [Int]) output =
			(Cons (-1) output);
	     print :: ([Int] -> Int -> [Int]) output x =
			(Cons x output);
             constrain :: (Int -> Int) x =
                        x % 16;
	     getMem :: ([Int] -> Int -> Int) mem index =
			if index == 0 then (head mem) else (getMem (tail mem) (index - 1));
	     setMem :: ([Int] -> Int -> Int -> [Int]) mem index value =
			if index == 0 then (Cons value (tail mem)) else (Cons (head mem) (setMem (tail mem) (index - 1) value));
             evalInstruction :: ([Int] -> [Int] -> Int -> Int -> Int -> [Int]) output mem r0 r1 ip =
			if (getMem mem ip) == 0 then eval' output mem r0 r1 ip else
			if (getMem mem ip) == 1 then eval' output mem (constrain (r0 + r1)) r1 (constrain ip + 1) else
			if (getMem mem ip) == 2 then eval' output mem (constrain (r0 - r1)) r1 (constrain ip + 1) else
			if (getMem mem ip) == 3 then eval' output mem (constrain (r0 + 1)) r1 (constrain ip + 1) else
			if (getMem mem ip) == 4 then eval' output mem r0 (constrain (r1 + 1)) (constrain ip + 1) else
			if (getMem mem ip) == 5 then eval' output mem (constrain (r0 - 1)) r1 (constrain ip + 1) else
			if (getMem mem ip) == 6 then eval' output mem r0 (constrain (r1 - 1)) (constrain ip + 1) else
			if (getMem mem ip) == 7 then eval' (ding output) mem r0 r1 (constrain ip + 1) else
			if (getMem mem ip) == 8 then eval' (print output (getMem mem (getMem mem (constrain (ip + 1))))) mem r0 r1 (constrain ip + 2) else
			if (getMem mem ip) == 9 then eval' output mem (getMem mem (constrain (ip + 1))) r1 (constrain ip + 2) else
			if (getMem mem ip) == 10 then eval' output mem r0 (getMem mem (getMem mem (getMem mem (constrain (ip + 1))))) (constrain ip + 2) else
			if (getMem mem ip) == 11 then eval' output (setMem mem (getMem mem (constrain ip + 1)) r0) r0 r1 (constrain ip + 2) else
			if (getMem mem ip) == 12 then eval' output (setMem mem (getMem mem (constrain ip + 1)) r1) r0 r1 (constrain ip + 2) else
			if (getMem mem ip) == 13 then eval' output mem r0 r1 (getMem mem (constrain (ip + 1))) else
			if (getMem mem ip) == 14 then eval' output mem r0 r1 (if r0 == 0 then (getMem mem (constrain (ip + 1))) else (constrain ip + 2)) else
			if (getMem mem ip) == 15 then eval' output mem r0 r1 (if r0 > 0  then (getMem mem (constrain (ip + 1))) else (constrain ip + 2)) else
			(Nil);
    in eval input;