#include<bits/stdc++.h>
using namespace std;

int main(){
  long long n,h,s;
  vector<long long> a;
  cin>>n>>h;
  
  for(long long i=0;i<n;i++){
    cin>>a[i];
  }
  
  for(long long i=0;i<n;i++){
      s*=a[i];
  }
  if(s/a.size()==0) cout<<"Yes"<<endl;
  else cout<<"No"<<endl;
 
    return 0;
}