import math


def pos(x, y, r, degree):
    rad = math.radians(degree)
    return (r * math.cos(rad) + x, r * math.sin(rad) + y)


def main():
    x, y, r = map(int, input().split())
    # first quadrant
    x, y = pos(abs(x), abs(y), r, 45)

    manhattan = 0
    for r in range(1, 500):
        if y < -x + r:
            manhattan = r
            break

    print(manhattan)


if __name__ == "__main__":
    main()