#include<bits/stdc++.h>
using namespace std;
int main()
{
	int n,m;
	cin>>n>>m;
	int sum=0;
	for(int i=1;i<=n;i++)
	{
		int x;
		cin>>x;
		if(i%2==0) sum--;
		sum+=x;
	}
	if(sum<=m)
	{
		cout<<"Yes";
	}
	else
	{
		cout<<"No";
	}
	return 0;
}