import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.StreamTokenizer;
import java.util.Arrays;
import java.util.Comparator;

class Main{
	static StreamTokenizer st=new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));
	public static void main(String[] args) throws IOException {
		int n=nextInt();
		int limStrength=nextInt();
		int bandeng=nextInt();
		int gao=nextInt();
		Ping[] arr=new Ping[n];
		for(int i=0;i<n;i++)
		{
			Ping p=new Ping();
			p.setGao(nextInt());
			
			if(p.getGao()<bandeng+gao)
			{
				p.setLi(nextInt());
			}
			else
			{
				nextInt();
				p.setLi(Integer.MAX_VALUE);
			}
			arr[i]=p;
		}
		Arrays.sort(arr,new Comparator<Ping>() {

			@Override
			public int compare(Ping o1, Ping o2) {
				// TODO 自动生成的方法存根
				return o1.getLi()-o2.getLi();
			}
		});
		int i=0;
		int count=0;
		while(i<n&&limStrength>=arr[i].getLi())
		{
			limStrength=limStrength-arr[i].getLi();
			count++;
			i++;
		}
		System.out.println(count);
	}
	static int nextInt() {
		try {
			st.nextToken();
		} catch (IOException e) {
		}
		return (int)st.nval;
	}
}
class Ping{
	int gao;
	int li;
	public int getGao() {
		return gao;
	}
	public void setGao(int gao) {
		this.gao = gao;
	}
	public int getLi() {
		return li;
	}
	public void setLi(int li) {
		this.li = li;
	}
}

如上,WA了第二个和第五个,求助