package main

import (
	"bufio"
	"fmt"
	"math"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)
var rdr = bufio.NewReaderSize(os.Stdin, 1000000)

func main() {
	sc.Split(bufio.ScanWords)
	a, b, s := nextFloat(), nextFloat(), nextFloat()
	count := 0

	if s == 1 {
		count += int(math.Abs(a - s))
		count += int(s)
		fmt.Println(count)
		return
	}

	if math.Abs(a-s) <= math.Abs(b-s) {
		count += int(math.Abs(a - s))
		count += int(s)
		fmt.Println(count)
		return
	}

	count += int(math.Abs(b - s))
	if math.Abs(s-1) <= math.Abs(s-a) && a != 0 {
		count += int(s) - 1
		count += int(a)
		fmt.Println(count)
		return
	}

	count += int(math.Abs(a - s))

	if a == 0 {
		count++
	} else {
		count += int(a)
	}
	fmt.Println(count)
}

func nextLine() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	i, _ := strconv.Atoi(nextLine())
	return i
}

func nextFloat() float64 {
	f, _ := strconv.ParseFloat(nextLine(), 64)
	return f
}