import sys

x = int(sys.stdin.readline())
y = int(sys.stdin.readline())
L = int(sys.stdin.readline())

if x == 0 and y == 0:
    print(0)
    sys.exit()

def compute_rotation_cost(current, target):
    clockwise = (target - current) % 4
    counter = (current - target) % 4
    return min(clockwise, counter)

if x == 0:
    if y >= 0:
        moves = (y + L - 1) // L
        print(moves)
    else:
        rotates = 2
        moves = (-y + L - 1) // L
        print(rotates + moves)
    sys.exit()

if y == 0:
    rotates = 1
    moves = (abs(x) + L - 1) // L
    print(rotates + moves)
    sys.exit()

# Both x and y are non-zero
# Case 1: Process Y first
y_dir = 0 if y >= 0 else 2
x_dir = 1 if x >= 0 else 3

rotate_y = 0 if y >= 0 else 2
current_after_y = y_dir
target_x = x_dir
rotate_x = compute_rotation_cost(current_after_y, target_x)
moves_y = (abs(y) + L - 1) // L
moves_x = (abs(x) + L - 1) // L
case1 = rotate_y + moves_y + rotate_x + moves_x

# Case 2: Process X first
x_dir_case = 1 if x >= 0 else 3
y_dir_case = 0 if y >= 0 else 2

rotate_x_case = 1  # Rotate from North to East/West (1 step)
current_after_x = x_dir_case
target_y_case = y_dir_case
rotate_y_case = compute_rotation_cost(current_after_x, target_y_case)
moves_x_case = (abs(x) + L - 1) // L
moves_y_case = (abs(y) + L - 1) // L
case2 = rotate_x_case + moves_x_case + rotate_y_case + moves_y_case

print(min(case1, case2))