def main():
    x = int(input())
    y = int(input())
    max_length = int(input())
    if x == 0 and y > 0:
        operation = 0
    elif y < 0:
        operation = 2
    else:
        operation = 1
    operation += abs(x // max_length + x % max_length)
    operation += abs(y // max_length + y % max_length)
    print(operation)


if __name__ == '__main__':
    main()