import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int A = scan.nextInt();
		int B = scan.nextInt();
		int S = scan.nextInt();
		scan.close();
		int l1 = Math.abs(S - A);
		int l2 = Math.abs(S - B);
		if(l1 < l2) {
			int ans = l1 + S;
			System.out.println(ans);
		}else {
			int ans = l2;
			if(A >= S) {
				if(A - S >= S) {
					ans += S + A - 1;
				}else {
					ans += A - S + A;
				}
			}else {
				ans += S - A + A;
			}
			System.out.println(ans);
		}
	}
}