int main( )
{
	int n,k,a[1000],i=0,j,t=0,flag=0;
	cin>>n>>k;
	for(t=0;t<=n-1;t++)                                     //?????
	{cin>>a[t];
	}
	for (i=0;i<=n-1;i++)
		{for(j=i+1;j<=n-1;j++)
		{   
			if(a[i]+a[j]==k) {flag=1;cout<<"yes";break;}	//????????????k
		}
		if(flag==1) break;                                  //????
	    }
	if(flag==0) cout<<"no";                                 //??????????
	return 0;
}
