import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

X,Y,L = map(int,read().split())

def solve(X,Y,L):
    if X == 0 and Y == 0:
        return 0
    if X == 0 and Y > 0:
        return (Y + L - 1) // L
    if X == 0 and Y < 0:
        return (-Y + L - 1) // L + 2
    # X != 0
    if X < 0:
        X = -X
    x = (X + L - 1) // L
    if Y >= 0:
        return 1 + x + (Y + L - 1) // L
    return 2 + x + (-Y + L - 1) // L

answer = solve(X,Y,L)
print(answer)