# 求めるべきはy = -x + kとの交点

x0, y0, r = map(int, input().split())
x0 = abs(x0)
y0 = abs(y0)

for k in range(x0+y0, x0+y0+500):
    a = 2
    b = -2*(x0+k-y0)
    c = x0**2+(k-y0)**2-r**2
    D = b**2-4*a*c
    if D < 0:
        print(k)
        break