#include <stdio.h>
#include <stdlib.h>


int main () 
{
  FILE * f ;
  int n,k,i,aux,j;
  int v[1000000] = {0};
	f =  fopen("sdo.in","r");
	fscanf(f,"%i%i",&n,&k);
	
	//v = (int*)malloc(1000000*sizeof(int));
	for (i = 0; i < n;i++){
		fscanf(f,"%i",&aux);
		v[aux] = v[aux]+1; 
	}	
	i = 0;
	j = 0;

	while(i <=k-1){

	if(v[i] != 0){
		j = i;
		i = i +v[i];	
	}
i++;

	}
	fclose(f);
	//printf("%d",j);
      f = fopen("sdo.out","w");
      
      fprintf(f,"%i",j);
      fclose(f);






	return 0;
}