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 = 0;
    if(Math.abs(a - s) <= Math.abs(b - s)) {
      ans = Math.abs(a - s) + s;
    } else {
      ans = Math.abs(b - s) + Math.abs(a - s) + a;
      if(a == 0) ans++;
    }
    if(s == 1) ans = Math.abs(a - s) + 1;
    System.out.println(ans);
  }
}