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

des = [X , Y] #destination
Lobot = [0, 0]
count = 0


while des[1] != Lobot[1]:
    if abs(des[1] - Lobot[1]) > L:
        if des[1] < 0:
            n = (abs(des[1] - Lobot[1]) - 1) // L
            Lobot[1] -= n * L
        else:
            n = (abs(des[1] - Lobot[1]) - 1) // L
            Lobot[1] += n * L
        count += n
    else:
        Lobot[1] = des[1]
        count += 1

while des[0] != Lobot[0]:
    if abs(des[0] - Lobot[0]) > L:
        if des[0] < 0:
            n = (abs(des[0] - Lobot[0]) - 1) // L
            Lobot[0] -= n * L
        else:
            n = (abs(des[0] - Lobot[0]) - 1) // L
            Lobot[0] += n * L
        count += n
    else:
        Lobot[0] = des[0]
        count += 1

if des[1] >= 0 and des[0] != 0:
    count += 1
elif des[1] < 0:
    count += 2
elif des[1] >= 0 and des[0] == 0:
    count += 0
else:
    count += 0

print(count)