Task: Question Understanding
Input (English): Suppose 4 - 1 = 3*p + 5*n, -3*n - 9 = 0. Let d(c) = c**2 - 6*c. Let m be d(p). Suppose 2*q - 23 = b, m = -0*q + 4*q + 3*b - 21. What is the units digit of q?
Output (English): numbers