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

public class Main {
    static House[] houses;
    static ArrayList<HashMap<Integer, Integer>> dp = new ArrayList<>();
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        houses = new House[n];
        for (int i = 0; i < n; i++) {
            houses[i] = new House(sc.nextInt(), sc.nextInt());
            dp.add(new HashMap<>());
        }
        Arrays.sort(houses);
        System.out.println(dfw(n - 1, 0));
    }
    
    static int dfw(int idx, int v) {
        if (idx < 0) {
            return v;
        }
        if (!dp.get(idx).containsKey(v)) {
            if (houses[idx].limit > v) {
                dp.get(idx).put(v, Math.max(dfw(idx - 1, v), dfw(idx - 1, v + houses[idx].value)));
            } else {
                dp.get(idx).put(v, dfw(idx - 1, v));
            }
        }
        return dp.get(idx).get(v);
    }
    
    static class House implements Comparable<House> {
        int value;
        int limit;
        
        public House(int value, int limit) {
            this.value = value;
            this.limit = limit;
        }
        
        public int compareTo(House another) {
            return (another.limit + another.value) - (limit + value);
        }
    }
} 
class Utilities {
    static String arrayToLineString(Object[] arr) {
        return Arrays.stream(arr).map(x -> x.toString()).collect(Collectors.joining("\n"));
    }
    
    static String arrayToLineString(int[] arr) {
        return String.join("\n", Arrays.stream(arr).mapToObj(String::valueOf).toArray(String[]::new));
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public int[] nextIntArray() throws Exception {
        return Stream.of(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray();
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
    
}