import math

x,y,r = [int(i) for i in input().split()]

x_sign = -1 if(x<0) else 1
y_sign = -1 if(y<0) else 1
x_max = x+r/(math.sqrt(2))*x_sign
y_max = y+r/(math.sqrt(2))*y_sign

print(math.ceil(abs(x_max)+abs(y_max)))