#include<bits/stdc++.h>

using namespace std;
using ll = long long;

const int N = 1005;
int n, idx[N];
ll w[N], s[N], dp[2][N];

int main() {
    scanf("%d", &n);
    for (int i = 1; i <= n; i++) {
        scanf("%d %d", &w[i], &s[i]);
        idx[i] = i;
    }
    sort(idx + 1, idx + n + 1, [&] (int a, int b) {
        return w[a] + s[a] < w[b] + s[b];
    });
    for (int j = 1; j <= n; j++) dp[0][j] = 1e18;
    for (int i = 1; i <= n; i++) {
        for (int j = 0; j <= n; j++) dp[i & 1][j] = 1e18;
        for (int j = 0; j <= i; j++) {
            dp[i & 1][j] = dp[!(i & 1)][j];
            if (j && dp[!(i & 1)][j - 1] <= s[idx[i]]) {
                dp[i & 1][j] = min(dp[i & 1][j], dp[!(i & 1)][j - 1] + w[idx[i]]);
            }
        }
    }
    int ans = 0;
    for (int j = 1; j <= n; j++) {
        if (dp[n & 1][j] != 1e18) ans = j;
    }
    printf("%d", ans);
}