a = (7 - 5) * 4 = 2 * 4 = 8;
b = a mod 3 + 15 = 8 mod 3 + 15 = 2 + 15 = 17;
a = b div 4 + 3 = 17 div 4 + 3 = 4 + 3 = 7.
a = (7 - 5) * 4 = 2 * 4 = 8;
b = a mod 3 + 15 = 8 mod 3 + 15 = 2 + 15 = 17;
a = b div 4 + 3 = 17 div 4 + 3 = 4 + 3 = 7.