//#include <bits/stdc++.h>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <algorithm>
#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <stdio.h>
#include <queue>
#include <stack>;
#include <map>
#include <set>
#include <string.h>
#include <vector>
#define ME(x , y) memset(x , y , sizeof(x))
#define SF(n) scanf("%d" , &n)
#define rep(i , n) for(int i = 0 ; i < n ; i ++)
#define INF  0x3f3f3f3f
#define mod 998244353
#define PI acos(-1)
using namespace std;
typedef long long ll ;
int dp[200005];
int w[209] , val[209];


int main()
{
    int n ;
    while(~scanf("%d" , &n))
    {
        for(int i = 0 ; i <= 200000 ; i++)
            dp[i] = -INF ;
        dp[100000] = 0 ;
        for(int i = 1 ; i <= n ; i++)
        {
            scanf("%d%d" , &w[i] , &val[i]);
        }
        for(int i = 1 ; i <= n ; i++)
        {
            if(w[i] < 0 && val[i] < 0)
                continue ;
            if(w[i] > 0)
            {
                for(int j = 200000 ; j >= w[i] ; j--)
                {
                    if(dp[j-w[i]] > -INF)
                    dp[j] = max(dp[j] , dp[j-w[i]]+val[i]);
                }
            }
            else
            {
                for(int j = w[i] ; j <= 200000 + w[i] ; j++)
                {
                    if(dp[j-w[i]] > -INF)
                    dp[j] = max(dp[j] , dp[j-w[i]]+val[i]);
                }
            }
        }
        int ans = -INF ;
        for(int i = 100000 ; i <= 200000 ; i++)
        {
            if(dp[i] >= 0)
            {
                ans = max(ans , dp[i]+i-100000);
            }
        }
        cout << ans << endl;
    }


    return 0 ;
}