package main

import (
	"fmt"
	"math"
)

func main() {
	var x, y, r int
	fmt.Scanf("%d %d %d", &x, &y, &r)

	fmt.Println(int(
		math.Abs(float64(x)) +
		math.Abs(float64(y)) +
		math.Ceil(math.Sqrt(2) * float64(r))))
}