X, Y, L = [int(input()) for _ in range(3)]

y1 = (Y+L-1) // L
y2 = (-Y+L-1) // L
x = (abs(X)+L-1) // L

cnt = 0
if Y >= 0 and X != 0:
    cnt += y1
    cnt += x + 1

elif Y >=0 and X == 0:
    cnt += y1

elif Y < 0 and X != 0:
    cnt += y2 + 1
    cnt += x + 1

elif Y < 0 and X == 0:
    cnt += y2 + 2

print(cnt)