#include<stdio.h>
#include<stdlib.h>

struct kaaala
{
	int x,y;
}a[10001];

int n,s;

bool flag;

int cmp(const void *a,const void *b)
{
	return (*(kaaala *)a).y-(*(kaaala *)b).y;
}

int main()
{
	freopen("toybrick.in","r",stdin);
	freopen("toybrick.out","w",stdout);
	int i;
	while(1)
	{
		scanf("%d%d",&n,&s);
		if(n==0&&s==0)
		{
			break;
		}
		for(i=1;i<=n;i++)
		{
			scanf("%d%d",&a[i].x,&a[i].y);
		}
		qsort(a+1,n,sizeof(kaaala),cmp);
		flag=true;
		for(i=1;i<=n;i++)
		{
			if(s>=a[i].y)
			{
				s+=a[i].x;
			}
			else
			{
				flag=false;
				break;
			}
		}
		if(flag)
		{
			printf("YES\n");
		}
		else
		{
			printf("NO\n");
		}
	}
	return 0;
}