#include <iostream>
#define INF (2 << 24)
using namespace std;

int n, v[11111], t[11111];
int dp[10001][10001];

int rec(int sum, int home){

  if(dp[sum][home]) return dp[sum][home];
  int ret = 0;
  bool judge = true;
  for(int i = 0; i < n; i++){
    if(sum < t[i]){
      ret = max(ret, rec(sum + v[i], home + 1) + v[i]);
      judge = false;
    }
  }
  if(judge) return 0;
  return dp[sum][home] = ret;
}
    
int main(){
  
  cin >> n;
  for(int i = 0; i < n; i++){
    cin >> v[i] >> t[i];
  }
  
  cout << rec(0, 0) << endl;
}