Create a woodpecker script that takes 16-bit a and 16-bit b and calculates the 16-bit sum modulo 2**16 - 17 (65519) (a+b) % (2**16-17).
a<65519, b<65519 is guaranteed.
<low a hi> | <low b hi> | <low output hi>
------------------------------------------------------
0000000000000000 | 0000000000000000 | 0000000000000000
1000000000000000 | 1000000000000000 | 0100000000000000
1000000000000000 | 1111000000000000 | 0000100000000000
1010001000000000 | 0010010110000000 | 1001011110000000
0111011111111111 | 1000000000000000 | 0000000000000000
0111011111111111 | 0111011111111111 | 1011011111111111