s22 -> s20
s20 -> s22
s19 -> s17
s17 -> s19
s16 + s17 -> s28
s28 -> s16 + s17
s28 -> s26
s26 -> s27
s26 -> s28
s27 -> s26
s27 -> s16 + s17
s25 -> s14
s14 -> s25
s21 -> s23