import java.util.*;

public class Main {
    static ArrayList<HashMap<Integer, Integer>> paid = new ArrayList<>();
    static ArrayList<HashMap<Integer, Integer>> free = new ArrayList<>();
    static Pizza[] pizzas;
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int k = sc.nextInt();
		pizzas = new Pizza[n];
		for (int i = 0; i < n; i++) {
		    pizzas[i] = new Pizza(sc.nextInt(), sc.nextInt());
		    paid.add(new HashMap<>());
		    free.add(new HashMap<>());
		}
		Arrays.sort(pizzas);
		System.out.println(dfw(n - 1, k, true));
   }
   
   static class Pizza implements Comparable<Pizza> {
       int price;
       int value;
       
       public Pizza(int price, int value) {
           this.price = price;
           this.value = value;
       }
       
       public int compareTo(Pizza another) {
           return price - another.price;
       }
   }
   
   static int dfw(int idx, int cost, boolean isPaid) {
       if (cost < 0) {
           return Integer.MIN_VALUE;
       }
       if (idx < 0) {
           return 0;
       }
       if (isPaid) {
           if (paid.get(idx).containsKey(cost)) {
               return paid.get(idx).get(cost);
           }
           int ans = Math.max(dfw(idx - 1, cost, true), dfw(idx - 1, cost - pizzas[idx].price, false) + pizzas[idx].value);
           paid.get(idx).put(cost, ans);
           return ans;
       } else {
           if (free.get(idx).containsKey(cost)) {
               return free.get(idx).get(cost);
           }
           int ans = Math.max(dfw(idx - 1, cost, true) + pizzas[idx].value, dfw(idx - 1, cost, false));
           free.get(idx).put(cost, ans);
           return ans;
       }
   }
}