def count_prog(start, end, prog):
    distance = end - start
    if distance < 0:
        distance *= -1
    if distance % prog == 0:
        count = distance // prog
    else:
        count = (distance // prog) + 1
    return count


(TARGET_X) = int(input().rstrip())
(TARGET_Y) = int(input().rstrip())
(MAX_PROG) = int(input().rstrip())

nof_ope = 0

# 回転する回数を数える
#   ---Y---
#   |+|0|-|
# |+|1|1|2|
# X0|0|-|2|
# |-|1|1|2|
if TARGET_Y < 0:
    nof_ope += 2
elif TARGET_Y == 0:
    nof_ope += 1
elif TARGET_X != 0:
    nof_ope += 1

# 南北の移動回数を求める
nof_ope += count_prog(0, TARGET_Y, MAX_PROG)
# 東西の移動回数を求める
nof_ope += count_prog(0, TARGET_X, MAX_PROG)

print(nof_ope)