import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.InputStream;
import java.io.PrintWriter;
import java.lang.reflect.Array;
import java.math.BigDecimal;
import java.math.MathContext;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.Deque;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.PriorityQueue;
import java.util.Queue;
import java.util.Random;
import java.util.Scanner;
import java.util.Set;
import java.util.Stack;
import java.util.TreeMap;
import java.util.TreeSet;

import static java.util.Comparator.*;

public class Main {
    public static void main(String[] args) {
        PrintWriter out = new PrintWriter(System.out);
        Solver solver = new Solver(System.in, out);
        solver.solve();
        out.close();
    }
}
class Solver {
	Scanner sc;
	PrintWriter out;
    public Solver(InputStream in, PrintWriter out) {
    	sc = new Scanner(in);
    	this.out = out;
    }
    // ==================================================================
	int[][][] dp = new int[2][5010][2];	// [交互に使う][金額][次にタダでもらえるなら １ ]
										// [5000][5000][2] は取らない・・・
	List<PP> list = new ArrayList<>();
	public void solve() {
		int N = ni();
		int K = ni();
		int p, d;
		for (int i = 0; i < N; i++) {
			p = ni();
			d = ni();
			list.add(new PP(p, d));
		}
		list.sort(comparing(PP::getKey, reverseOrder()));
		for (int i = 0; i < 5010; i++) {
			dp[0][i][0] = -1000000000;	dp[0][i][1] = -1000000000;
			dp[1][i][0] = -1000000000;	dp[1][i][1] = -1000000000;
		}
		dp[0][0][0] = 0;
		int from = 0, to = 1;
		for (int i = 0; i < N; i++) {
			for (int j = 0; j <= K; j++) {
				// 買わない　かつ　もらわない
				dp[to][j][0] = Math.max(dp[to][j][0], dp[from][j][0]);
				dp[to][j][1] = Math.max(dp[to][j][1], dp[from][j][1]);
				// 買う
				if((j + list.get(i).key) <= K) {
//					dp[to][j + PD[i][0]][0] = Math.max(dp[to][j + PD[i][0]][0], 
//														dp[from][j][0] + PD[i][1]);
					dp[to][j + list.get(i).key][1] = Math.max(dp[to][j + list.get(i).key][1], 
														dp[from][j][0] + list.get(i).val);
					dp[to][j + list.get(i).key][1] = Math.max(dp[to][j + list.get(i).key][1], 
														dp[from][j][1] + list.get(i).val);
				}
				// もらう
				dp[to][j][0] = Math.max(dp[to][j][0], dp[from][j][1] + list.get(i).val);
			}
			from = (from + 1) % 2;
			to = (to + 1) % 2;
		}
		int ans =  0;
		for (int i = 0; i <= K; i++) {
//			out.println("dp[" + from + "][" + i + "][0] = " + dp[from][i][0]);
//			out.println("dp[" + from + "][" + i + "][1] = " + dp[from][i][1]);
			ans = Math.max(ans, dp[from][i][0]);
			ans = Math.max(ans, dp[from][i][1]);
//			out.println(" --> ans = " + ans);
		}
		out.println(ans);
	}
    class PP{
    	public int key, val;
    	public PP(int key, int val) {
    		this.key = key;
    		this.val = val;
    	}
		public int getKey() {
			return key;
		}
		public void setKey(int key) {
			this.key = key;
		}
		public int getVal() {
			return val;
		}
		public void setVal(int val) {
			this.val = val;
		}
    }
    // ------------------------------------------
    // 入力
    // ------------------------------------------
    public int ni() {
    	return sc.nextInt();
    }
    public long nl() {
    	return sc.nextLong();
    }
    public String ns() {
    	return sc.next();
    }
    public char[] nc() {
    	return sc.next().toCharArray();
    }
    public int[] ndi(int N) {
    	int[] ans = new int[N];
    	for (int i = 0; i < N; i++) {
			ans[i] = ni();
		}
    	return ans;
    }
    public long[] ndl(int N) {
    	long[] ans = new long[N];
    	for (int i = 0; i < N; i++) {
			ans[i] = nl();
		}
    	return ans;
    }
    public String[] nds(int N) {
    	String[] ans = new String[N];
    	for (int i = 0; i < N; i++) {
			ans[i] = ns();
		}
    	return ans;
    }
    public char[][] ndc(int N) {
    	char[][] ans = new char[N][];
    	for (int i = 0; i < N; i++) {
			ans[i] = nc();
		}
    	return ans;
    }
    public int[][] nddi(int N, int S) {
    	int[][] ans = new int[N][S];
    	for (int i = 0; i < N; i++) {
			for (int j = 0; j < S; j++) {
				ans[i][j] = ni();
			}
		}
    	return ans;
    }
}