# -*- coding: utf-8 -*-
"""
No.172 UFOを捕まえろ
https://yukicoder.me/problems/no/172

"""
import sys
from sys import stdin
from math import ceil, sqrt
input = stdin.readline


def main(args):
    x, y, r = map(int, input().split())
    ufo_center = abs(x) + abs(y)
    ufo_r = r * sqrt(2)
    print(ufo_center + ceil(ufo_r))


if __name__ == '__main__':
    main(sys.argv[1:])