X = int(input())
Y = int(input())
L = int(input())

step_x = abs(X) // L if abs(X) % L == 0 else abs(X) // L + 1
step_y = abs(Y) // L if abs(Y) % L == 0 else abs(Y) // L + 1

if Y >= 0 and X == 0:
    rotate = 0
elif Y >= 0:
    rotate  = 1
else:
    rotate = 2

print(step_x + step_y + rotate)