import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
    
		// 整数の入力
		int n = sc.nextInt();
		int m = sc.nextInt();
		int x = sc.nextInt();
      
        int[] list = new int[n + 1];
      
        for(int i = 0; i < m; i++) {
          list[sc.nextInt()]++;
        }
      
        int index = x;
        int ans1 = 0;
        while(index != n) {
          ans1 += list[index];
          index++;
        }
      
        index = x;
        int ans2 = 0;
        while(index != 0) {
          ans2 += list[index];
          index--;
        }
    
		// 出力
		System.out.println(Math.min(ans1, ans2));
	}
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz