function Main(input) {
    let first_line = input.split("\n")[0].split(" "),
    	x = Number(first_line[0]),
    	y = Number(first_line[1]),
    	r = Number(first_line[2])

    distance = Math.ceil(Math.abs(x) + Math.abs(y) + Math.sqrt(2) * r)
    console.log(distance)
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));