import math


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


def within(r, x, y):
    is_within = True
    # right top
    is_within &= y < -x + r
    # right bottom
    is_within &= y > x - r
    # left bottom
    is_within &= y > -x - r
    # left top
    is_within &= y < x + r
    return is_within


def main():
    x, y, r = map(int, input().split())

    x1, y1 = 0.0, 0.0
    if x >= 0 and y >= 0:
        x1, y1 = pos(x, y, r, 45)
    elif x >= 0 and y <= 0:
        x1, y1 = pos(x, y, r, 135)
    elif x <= 0 and y <= 0:
        x1, y1 = pos(x, y, r, 225)
    else:
        x1, y1 = pos(x, y, r, 315)

    manhattan = 0
    for i in range(0, 200):
        if within(i, x1, y1):
            manhattan = i
            break

    print(manhattan)


if __name__ == "__main__":
    main()