int main(){
	 int n ,k,i,j,a=0;
	 int dk[1000];
	 scanf("%d %d",&n,&k);
           scanf("%d",&(dk[0]));
	 for(i=1;i<n;i++){
		 scanf(" %d",&(dk[i]));
	 }
	 for(i=0;i<n-1;i++){
		 for(j=i+1;j<n;j++){
			 if(dk[i]+dk[j]==k){
				 printf("yes");
				 return 0;
			 }
		 }
		 a+=1;
	 }
	 if(a==n-1) printf("no");
	return 0;

}

