#include<stdio.h>
int main()
{
	int n,m;
	int count;
	int nu=0;
	scanf("%d%d",&n,&m);
	while(n>0)
	{
		scanf("%d",&count);
		while(--count)
		nu+=n;
		nu+=n;
		n--;
	}
	if(nu>=m)
	printf("Yes\n");
	else
	printf("No\n");
}