#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
ll T=1;const ll N=2e5+5;
ll n,x,y;
ll pre[N];ll a[N];ll ans=0;ll k;ll b[N];
void solve(){
	cin>>n;for(ll i=1;i<=n;++i){
		cin>>a[i];a[i]=a[i]*2;
	}
	for(ll i=1;i<=n;++i)cin>>b[i];
	sort(a+1,a+1+n);sort(b+1,b+1+n);
	ll l=1;ll r=1;
	while(l<=n&&r<=n){
		if(a[l]-b[r]>0){
			ans+=1;r++;l++;
		}else{
			l++;
		}
	}cout<<ans;
	
}

int main(){
	
	while(T--)solve();
	return 0;
}