import math


def move_count(length_for_one_move, length):
    if length == 0:
        return 0
    else:
        return math.ceil(length / length_for_one_move)


if __name__ == "__main__":
    X = int(input())
    Y = int(input())
    L = int(input())

    total_order_count = 0

    if Y >= 0:
        # Y軸方向へ前進
        total_order_count += move_count(L, Y)

        if not X == 0:
            # 90度回転
            total_order_count += 1

            # X軸方向へ前進
            total_order_count += move_count(L, abs(X))

    else:
        # 90度回転
        total_order_count += 1

        # X軸方向へ前進
        total_order_count += move_count(L, abs(X))

        # 90度回転
        total_order_count += 1

        # Y軸方向へ前進
        total_order_count += move_count(L, abs(Y))

    print(total_order_count)