import java.util.Scanner;
public class Main {
    public static void main(String[] args) throws Exception {
        Scanner koko = new Scanner(System.in);
        int a = koko.nextInt();
        int b = koko.nextInt();
        int s = koko.nextInt();
        int dista = Math.abs(a-s);
        int distb = Math.abs(b-s);
        int min;
        if(dista<=distb){
            min = dista+s;
        }else if(distb<dista&&s==1){
            min = dista+1;
        }else if(distb<dista&&a>b){
            if(dista>=s){
                min = distb+s+a-1;
            }else{
                min = distb+dista+a;
            }
        }else if(distb<dista&&a==0){
            min = distb+s+1;
        }
         else{
            min = distb+dista+a;
        }
        System.out.println(min);
    }    
}