include <bits/stdc++.h>

using namespace std; const int N=1e5+1; long long a[N],b[N],n,s,c[N]; int main() { long long cnt=0; cin >> n >> s; for(long long i=1;i<=n;i++){

 cin >> a[i] >> b[i]; 
}
for(long long i=1;i<=n;i++){
    c[i]=b[i]-a[i]; 

}
sort(c+1,c+n+1); 
for(long long i=n;i>=1;i--)
{ 
    if(s+c[i]>=0)
    {
        s+=c[i]; 
        cnt++; 

    }else break; 

}
cout << cnt;
}