import java.io.*;
import java.util.*;

class Main {
	public static void main(String[] args) {
		new Main().run();
	}
	
	void run() {
		Scanner sc=new Scanner(System.in);
		int N=sc.nextInt();
		int K=sc.nextInt();
		int[] P=new int[N+1];
		int[] D=new int[N+1];
		int[][] a=new int[N+1][2];
		for(int i=0;i<N;++i){
			P[i]=sc.nextInt();
			D[i]=sc.nextInt();
		}
		P[N]=0;
		D[N]=0;
		for(int i=0;i<=N;++i){
			a[i][0]=P[i];
			a[i][1]=D[i];
		}
		Arrays.sort(a,new Comparator<int[]>(){
			public int compare(int[] a,int[] b){
				if(a[0]!=b[0])
					return Integer.compare(a[0],b[0]);
				else
					return Integer.compare(a[1],b[1]);
			}
		});
		++N;
		int[][] dp=new int[K+1][N];
		int[][] ma=new int[K+1][N];
		for(int i=0;i<=K;++i){
			for(int j=0;j<N;++j){
				dp[i][j]=-Integer.MAX_VALUE/3;
				ma[i][j]=-Integer.MAX_VALUE/3;
			}
		}
		int[][] seg=new int[K+1][N+10];
		for(int i=0;i<=K;++i){
			for(int j=0;j<N;++j){
				dp[i][j]=Math.max((i>0?dp[i-1][j]:0),(j>0?dp[i][j-1]:0));
				ma[i][j]=Math.max((i>0?ma[i-1][j]:0),(j>0?ma[i][j-1]:0));
				if(i-a[j][0]>=0){
					dp[i][j]=Math.max(dp[i][j],a[j][1]+(j>0?seg[i-a[j][0]][j-1]:0));
				}
				if(j+1<N)
					seg[i][j+1]=Math.max(seg[i][j+1],dp[i][j]+a[j+1][1]);
					seg[i][j+1]=Math.max(seg[i][j+1],seg[i][j]);
			}
		}
		System.out.println(dp[K][N-1]);
	}
}