package main

import (
	"fmt"
	"math"
)

func abs(x int) int {
	if x < 0 {
		return -x
	}
	return x
}

func main() {
	var X, Y, R int
	fmt.Scan(&X, &Y, &R)
	z := abs(X) + abs(Y)
	res := int(math.Ceil(math.Sqrt(2.0)*float64(R) + float64(z)))
	fmt.Println(res)
}