import sys; input = sys.stdin.buffer.readline
sys.setrecursionlimit(10**7)
from collections import defaultdict
con = 10 ** 9 + 7; INF = float("inf")

def getlist():
	return list(map(int, input().split()))

#処理内容
def main():
	x, y, r = getlist()
	x, y = abs(x), abs(y)
	for i in range(1, 600):
		if i > x + y and (i - x - y) ** 2 > 2 * (r ** 2):
			print(i)
			return
	
if __name__ == '__main__':
	main()