#include<bits/stdc++.h>
//ios::sync_with_stdio(false);cin.tie(0);
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<pii,int> ppii;
typedef pair<int,pii> pipi;
typedef pair<ll,ll> pll;
typedef pair<pll,ll> ppll;
typedef pair<ll,pll> plpl;
typedef tuple<ll,ll,ll> tl;
ll mod=1000000007;
ll mod2=998244353;
ll mod3=1000003;
ll mod4=998244853;
ll inf=1000000000000000000;
double pi=2*acos(0);
#define rep(i,m,n) for(int i=m;i<n;i++)
#define rrep(i,n,m) for(int i=n;i>=m;i--)
int dh[4]={1,-1,0,0};
int dw[4]={0,0,1,-1};
int ddh[8]={-1,-1,-1,0,0,1,1,1};
int ddw[8]={-1,0,1,-1,1,-1,0,1};
ll lmax(ll a,ll b){
    if(a<b)return b;
    else return a;
}
ll lmin(ll a,ll b){
    if(a<b)return a;
    else return b;
}
ll gcd(ll a,ll b){
    if(a<b)swap(a,b);
    if(b==0)return a;
    if(a%b==0)return b;
    return gcd(b,a%b);
}
ll Pow(ll n,ll k){
    ll ret=1;
    ll now=n;
    while(k>0){
        if(k&1)ret*=now;
        now*=now;
        k/=2;
    }
    return ret;
}
ll gya[1000010];
ll kai[1000010];
ll beki(ll n,ll k,ll md){
  ll ret=1;
  ll now=n;
  while(k>0){
    if(k%2==1){
      ret*=now;
      ret%=md;
    }
    now*=now;
    now%=md;
    k/=2;
  }
  return ret;
}
ll gyaku(ll n,ll md){
  return beki(n,md-2,md);
}
void nckinit(ll n,ll md){
  kai[0]=1;
  kai[1]=1;
  for(int i=2;i<=n;i++){
    kai[i]=kai[i-1]*i;
    kai[i]%=md;
  }
  gya[n]=gyaku(kai[n],md);
  for(int i=n-1;i>=1;i--){
    gya[i]=gya[i+1]*(i+1);
    gya[i]%=md;
  }
  gya[0]=1;
}
ll nck(ll n,ll k,ll md){
  if(k<0)return 0;
  if(k==0||n==k)return 1;
  ll ret=kai[n];
  ret*=gya[n-k];
  ret%=md;
  ret*=gya[k];
  ret%=md;
  return ret;
}
ll npk(ll n,ll k,ll md){
  if(k<0)return 0;
  if(k==0)return 1;
  ll ret=kai[n];
  ret*=gya[n-k];
  ret%=md;
  return ret;
}

int main(){
    ios::sync_with_stdio(false);cin.tie(0);
    int n;cin>>n;
    int h[n],p[n];
    rep(i,0,n)cin>>h[i]>>p[i];
    vector<int> vv[n];
    int num[n];
    fill(num,num+n,0);
    rep(i,0,n-1){
        rep(j,i+1,n){
            int f=h[i]-p[j];
            int g=h[j]-p[i];
            if(f>g){
                num[j]++;
                vv[i].push_back(j);
                
            }
            else if(f<g){
                num[i]++;
                vv[j].push_back(i);
                
            }
            else{
                if(h[i]<h[j]){
                    num[j]++;
                    vv[i].push_back(j);
                }
                else{
                    num[i]++;
                    vv[j].push_back(i);
                }
            }
        }
    }
    
    queue<int> q;
    vector<int> w;
    rep(i,0,n){
        if(num[i]==0)q.push(i);
    }
    while(q.size()>0){
        int now=q.front();q.pop();
        w.push_back(now);
        rep(i,0,vv[now].size()){
            int ne=vv[now][i];
            num[ne]--;
            if(num[ne]==0){
                q.push(ne);
            }
        }
    }
    reverse(w.begin(),w.end());
    int dp[n+1][n+1];
    rep(i,0,n+1)rep(j,0,n+1)dp[i][j]=2000000010;
    dp[0][0]=0;
    rep(i,0,n){
        rep(j,0,n+1){
            
            dp[i+1][j]=min(dp[i+1][j],dp[i][j]);
            int nh=h[w[i]];
            if(nh<dp[i][j])continue;
            dp[i+1][j+1]=min(dp[i+1][j+1],dp[i][j]+p[w[i]]);
        }
    }
    rrep(i,n,0){
        if(dp[n][i]<2000000010){
            cout<<i<<endl;
            return 0;
        }
    }
}


Measured memory_bytes: 167168