#include <bits/stdc++.h>
#define rep(i,n) for(int i=0; i<(int)(n); i++)

using namespace std;
using LL = long long;

int main(){
    int N;
    cin >> N;
    vector<int> a(N), b(N);
    rep(i,N) cin >> a[i];
    rep(i,N) cin >> b[i];
    LL ans=0;
    vector<int> c(N);
    rep(i,N) c[i]=i;
    do{
        LL res=0;
        rep(i,N){
            int A=a[c[i]];
            rep(j,i+1) if(A>b[j]) res++;
        }
        ans=max(ans,res);

    }while(next_permutation(c.begin(),c.end()));
    cout << ans << endl;

    return 0;
}