import java.util.*;

public class Main {
    static House[] houses;
    static int[][] dp;
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        houses = new House[n];
        for (int i = 0; i < n; i++) {
            houses[i] = new House(sc.nextInt(), sc.nextInt());
        }
        Arrays.sort(houses);
        dp = new int[n][10001];
        for (int[] arr : dp) {
            Arrays.fill(arr, -1);
        }
        System.out.println(dfw(n - 1, 0));
    }
    
    static int dfw(int idx, int value) {
        if (idx < 0) {
            return 0;
        }
        if (dp[idx][value] < 0) {
            dp[idx][value] = dfw(idx - 1, value);
            if (houses[idx].limit > value) {
                dp[idx][value] = Math.max(dp[idx][value], dfw(idx - 1, value + houses[idx].gain) + houses[idx].gain);
            }
        }
        return dp[idx][value];
    }
    
    static class House implements Comparable<House> {
        int gain;
        int limit;
        
        public House(int gain, int limit) {
            this.gain = gain;
            this.limit = limit;
        }
        
        public int compareTo(House another) {
            return another.limit + another.gain - limit - gain;
        }
    }
}