import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.Scanner;

public class Yuki054 {
    public static void main(String[] args) {
        Yuki054 hoge = new Yuki054();
    }

    Yuki054() {
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        int[] datas = new int[N];
        for (int i = 0; i < N; i++) {
            int V = scanner.nextInt();
            int T = scanner.nextInt();
            datas[i] = T * 100001 + V;
        }
        Arrays.sort(datas);
        int[] dp = new int[100001];
        Arrays.fill(dp, -1);
        dp[0] = 0;
        for (int i = 0; i < N; i++) {
            int V = datas[i] % 10001;
            int T = datas[i] / 10001;
            for (int j = V; j >= 0; j--) {
                if (dp[j] == -1) {
                    int K = Math.min(j + T, 10000);
                    dp[K] = Math.max(dp[K], dp[j] + T);
                }
            }
        }
        Arrays.sort(dp);
        System.out.println(dp[dp.length - 1]);
    }

}