Problem:
Score : 200 points

Problem Statement

There are N + 1 squares arranged in a row, numbered 0, 1, ..., N from left to right.

Initially, you are in Square X.
You can freely travel between adjacent squares. Your goal is to reach Square 0 or Square N.
However, for each i = 1, 2, ..., M, there is a toll gate in Square A_i, and traveling to Square A_i incurs a cost of 1.
It is guaranteed that there is no toll gate in Square 0, Square X and Square N.

Find the minimum cost incurred before reaching the goal.

Constraints

1 \leq N \leq 100

1 \leq M \leq 100

1 \leq X \leq N - 1

1 \leq A_1 < A_2 < ... < A_M \leq N

A_i \neq X

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N M X
A_1 A_2 ... A_M

Output

Print the minimum cost incurred before reaching the goal.

Sample Input 1

5 3 3
1 2 4

Sample Output 1

1

The optimal solution is as follows:

First, travel from Square 3 to Square 4. Here, there is a toll gate in Square 4, so the cost of 1 is incurred.

Then, travel from Square 4 to Square 5. This time, no cost is incurred.

Now, we are in Square 5 and we have reached the goal.

In this case, the total cost incurred is 1.

Sample Input 2

7 3 2
4 5 6

Sample Output 2

0

We may be able to reach the goal at no cost.

Sample Input 3

10 7 5
1 2 3 4 6 8 9

Sample Output 3

3

Solution in Java7 (OpenJDK 1.7.0) (judge verdict: Accepted)

 import java.util.ArrayList;
import java.util.Scanner;
 class Main  {
     public static void main(String[]args){
         Scanner scan = new Scanner(System.in);
         int n = scan.nextInt();
         int m = scan.nextInt();
         int x = scan.nextInt();
         ArrayList<Integer> a = new ArrayList<>();
         for(int i = 0 ; i<m;i++){
             a.add(scan.nextInt());
         }
         int max ;
  
         int cost = 0 ;
         for(int i = 1 ; i< x ; i++){
             if(a.contains(i)){
                 cost++;
             }
         }
         
         int cost2 = 0 ;
         for(int i = x+1 ; i< n+1 ; i++){
             if(a.contains(i)){
                 cost2++;
             }
         }
         System.out.println(Math.min(cost,cost2));
     }
}