import sys
if sys.platform =='ios':
	import clipboard
	a=clipboard.get()
	a = a.split('\n')
	text = '\n'.join(a)
	with open('input_file.txt','w') as f:
		f.write(text)
	sys.stdin = open('input_file.txt')
	
x,y,r = map(int,input().split())

import math
l = math.sqrt(2)
z = r*l
ans = abs(x)+abs(y)+int(z)+1

print(ans)