#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

const int INF = 1 << 28;
const int dp_size = 10010;

int N;
vector<pair<int, int>> house;

int dp[dp_size];

int main(){
    cin >> N;
    
    for(int i=0;i<N;i++){
        int V, T;
        cin >> V >> T;
    
        house.push_back(make_pair(T, V));
    }
    
    sort(house.begin(), house.end());

    for(int i=0;i<dp_size;i++)dp[i] = -INF;
    dp[0] = 0;
    
    for(int i=0;i<N;i++){
        int T = house[i].first;
        int V = house[i].second;
        
        for(int t=T-1;t>=0;t--)if(dp[t] != -INF){
            int nt = min(t + V, 10000);
            dp[nt] = max(dp[nt], dp[t] + V);
        }
    }
    
    int res = -INF;
    for(int t=0;t<=10000;t++)res = max(res, dp[t]);
 
    cout << res << endl;
    return 0;
}