import math
sq2 = 2 ** 0.5
x, y, r = map(int, input().split())
r2 = r/sq2
ne = abs(x + r2) + abs(y + r2)
se = abs(x + r2) + abs(y - r2)
sw = abs(x - r2) + abs(y - r2)
nw = abs(x - r2) + abs(y + r2)
print(math.floor(max(ne, se, sw, nw)) + 1)