import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int a = sc.nextInt();
		int b = sc.nextInt();
		int s = sc.nextInt();
		int ans;
		if (s == 1) {
		    if (a == 0) {
		        ans = 2;
		    } else {
		        ans = a;
		    }
		} else {
		    if (Math.abs(a - s) > Math.abs(b - s)) {
		        ans = Math.abs(b - s);
		        if (a == 0) {
		            ans += s - 1 + 2;
		        } else {
		            ans += Math.min(Math.abs(a - s) + a, s - 1 + a);
		        }
		    } else {
		        ans = Math.abs(s - a) + s;
		    }
		}
		System.out.println(ans);
	}
}