void asd(long long l,long long r,long long k){

 long long midd;

 if(l>r) {

 cout<<"NO"<<endl; return;

 }

 midd=(l+r)/2;

 if(a[midd]==k){

 cout<<"YES"<<endl;

 }

 else

 if(a[midd]>k) asd(l,midd-1,k);

 else asd(midd+1,r,k);

}

inline int cc(){

 freopen("binary1.in","r",stdin);

 freopen("binary1.out","w",stdout);

 cin>>n>>p;

 for(long long i=0;i<n;i++){

 cin>>a[i];

 }

 asd(0,n,p);

}