#include <iostream>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <tuple>
#include <cmath>
#include <numeric>
#include <functional>
#include <cassert>

#define debug_value(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << #x << "=" << x << endl;
#define debug(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << x << endl;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

using namespace std;
typedef long long ll;
using P = pair<int, int>;
const ll INF = 1e18;
ll dp[1005][1005];

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << setprecision(10) << fixed;
    int n; cin >> n;
    vector<ll> w(n), s(n);
    vector<P> vp(n);
    for(int i = 0; i < n; i++) {
        cin >> w[i] >> s[i];
        vp[i] = P(s[i]+w[i], i);
    }
    sort(vp.begin(), vp.end());
    for(int i = 0; i <= n; i++){
        for(int j = 0; j <= n; j++){
            dp[i][j] = INF;
        }
    }
    dp[0][0] = 0;
    for(int j = 0; j < n; j++){
        int i = vp[j].second;
        for(int k = 0; k <= j; k++){
            chmin(dp[j+1][k], dp[j][k]);
            if(dp[j][k] <= s[i]) chmin(dp[j+1][k+1], dp[j][k]+w[i]);
        }
    }
    for(int i = n; i >= 0; i--){
        if(dp[n][i] != INF){
            cout << i << endl;
            return 0;
        }
    }
}