#include<bits/stdc++.h>
using namespace std;
#define crap ios::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)

typedef long long int ll;
typedef unsigned long long ull;
typedef std::vector<int> vi;
typedef std::vector<ll> vll;
typedef std::vector<vi > vvi;
typedef std::vector<vll > vvll;
typedef std::pair<int,int> ii;
typedef std::pair< ll, ll > lp;
typedef std::vector<ii> vii;
typedef std::vector<vii > vvii;

#define int ll
#define pb push_back 
#define PB pop_back
#define pf push_front
#define PF pop_front
#define mp make_pair
#define ub(a,b) upper_bound(all(a),b)
#define lb(a,b) lower_bound(all(a),b)
#define bs(a,b) binary_search(all(a),b)
#define mem(a,b) memset(a,b,sizeof(a))
#define in(a,n) F(i,0,n-1)cin>>a[i]
#define in1(a,n) F(i,1,n)cin>>a[i]
#define out(a,n) F(i,0,n-1)cout<<a[i]<<" ";cout<<endl
#define ff first
#define ss second
#define F(i,a,b) for (ll i=a;i<=b;i++)
#define RF(i,a,b) for(ll i=a;i>=b;i--)
#define rep(i,n) F(i,0,n-1)
#define clr(a) (a).clear()
#define rz resize
#define sqr(a) ((a) * (a))
#define sz(a) int((a).size())
#define len(a) int((a).length())
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin() ,(a).rend()
#define endl '\n'

#define mod 1000000007
// #define mod 998244353

inline int add(int a, int b){a += b; if(a >= mod)a -= mod; return a;}
inline int sub(int a, int b){a -= b; if(a < 0)a += mod; return a;}
inline int mul(int a, int b){return (int)((long long) a * b %mod);}
inline int poww(int a, int b){int res = 1; while(b > 0){ if(b & 1)res = mul(res, a); a = mul(a, a);b /= 2;} return res;}
inline int inv(int a){return poww(a, mod - 2);}
int gcd(int a, int b, int &x, int &y){if(a == 0){x = 0, y = 1; return b;} int x1, y1;  int d = gcd(b%a, a, x1, y1); x = y1 - (b/a) * x1; y = x1; return d;}

// #################################### matrix operations ####################################
inline vvi matmul(vvi A, vvi B) {int p = A.size(), q = A[0].size();int r = B.size(), s = B[0].size();assert(q == r);vvi C(p, vi(s, 0LL));
	rep(i, p){rep(j, s){rep(k, q){
				// C[i][j] += A[i][k] * B[k][j]; 
				C[i][j] = add(C[i][j], mul(A[i][k], B[k][j]));
	}}}return C;}

inline vvi matpow(vvi A, int n){int p = A.size(), q = A[0].size();assert(p == q);vvi res(p, vi(p, 0));rep(i, p)res[i][i] = 1;while (n){if (n&1)res = matmul(res, A);A = matmul(A, A);n >>= 1;}return res;}

// ###########################################################################################

#define dbg(x) cout<<#x<<" :: "<<x<<endl;
#define dbg2(x,y) cout<<#x<<" :: "<<x<<"\t"<<#y<<" :: "<<y<<endl;
#define dbg3(x,y,z) cout<<#x<<" :: "<<x<<"\t"<<#y<<" :: "<<y<<"\t"<<#z<<" :: "<<z<<endl;
#define dbg4(x,y,z,w) cout<<#x<<" :: "<<x<<"\t"<<#y<<" :: "<<y<<"\t"<<#z<<" :: "<<z<<"\t"<<#w<<" :: "<<w<<endl;

//end of template

const int N = 5005;
int dp[N][N];
int n;
ii a[N];

bool comp(ii a, ii b){
	return (a.ff+a.ss) < (b.ff+b.ss);
}

const int INF = (ll)N * mod;

int go(int idx, int items){
	if (idx<0 && items > 0)
		return INF;
	if (items == 0)
		return 0;
	if (dp[idx][items] != -1)
		return dp[idx][items];
	int &ans = dp[idx][items];
	int take = go(idx-1, items - 1);
	int leave = go(idx-1, items);
	if (take <= a[idx].ff){
		ans = min(a[idx].ss+take, leave);
	}
	else{
		ans = leave;
	}
	return ans;
}

signed main(){
	crap;
	int x, y;
	cin >> n;
	rep(i, n){
		cin >> x >> y;
		a[i] = mp(x, y);
	}
	sort(a, a+n, comp);
	mem(dp, -1);
	RF(i, n, 1){
		if (go(n-1, i) != INF)
		{
			cout << i << endl;
			return 0;
		}
	}
	return 0;
}

Measured memory_bytes: 196224