也就这了·-·

#include<bits/stdc++.h>
using namespace std;
int n,a[10000],b[10000],aa[10000],ans=0;
int main()
{
    scanf("%d",&n);
    for (int i=1;i<=2*n;i++)
    {
        scanf("%d",&a[i]);
        aa[i]=1;
    }
    for (int i=1;i<=2*n;i++)
    {
        scanf("%d",&b[i]);
    }
    sort(a+1,a+2*n+1);
    sort(b+1,b+n+1);
    for (int i=1;i<=n;i++)
    {
        for (int j=1;j<=n;j++)
        {
            if ((aa[j]==1)&&(a[j]<b[i]))
            {
                aa[j]=0;
                ans+=1; 
                break;
            }
        }
    }
    for (int i=n+1;i<=2*n;i++)
    {
        for (int j=1;j<=n*2;j++)
        {
            if ((aa[j]==1)&&(a[j]>b[i]))
            {
                aa[j]=0;
                ans+=1; 
                break;
            }
        }
    } 
 cout<<ans<<endl;
 return 0;
}