x,y,r = map(int,input().split())
x, y = abs(x), abs(y)

#点と直線の距離  dis(ax + by + c = 0, (x0, y0))
def dis_point_to_line(a,b,c,x0,y0):
    if a == 0:
        ans = abs(y0-c/b)
    elif b == 0:
        ans = abs(x0-c/a)
    else:
        ans = abs(a*x0 + b*y0 + c)/((a**2 + b**2)**0.5)
    return(ans)

for i in range(x+y, 1000):
    ret = dis_point_to_line(1, 1, -i, x , y)
    if ret > r:
        print(i)
        exit()