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

Dx = abs(X)
Dy = abs(Y)

x_steps = (Dx + L - 1) // L if Dx != 0 else 0
y_steps = (Dy + L - 1) // L if Dy != 0 else 0

directions = 0
if x_steps > 0:
    directions += 1
if y_steps > 0:
    directions += 1

if directions == 0:
    print(0)
elif directions == 1:
    if y_steps > 0:
        print(y_steps)
    else:
        print(1 + x_steps)
else:
    print(y_steps + x_steps + 1)