#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <valarray>
#include <vector>

#define EPS 1e-9
#define INF 1070000000LL
#define MOD 1000000007LL
#define fir first
#define foreach(it,X) for(__typeof((X).begin()) it=(X).begin();it!=(X).end();it++)
#define ite iterator
#define mp make_pair
#define rep(i,n) rep2(i,0,n)
#define rep2(i,m,n) for(int i=m;i<(n);i++)
#define pb push_back
#define sec second
#define sz(x) ((int)x.size())

using namespace std;

struct timer{
	time_t start;
	timer(){start=clock();}
	~timer(){cerr<<1.*(clock()-start)/CLOCKS_PER_SEC<<" secs"<<endl;}
};

typedef istringstream iss;
typedef long long ll;
typedef pair<int,int> pi;
typedef stringstream sst;
typedef vector<int> vi;

int N,a[40010],b[40010];

int main(){
	cin.tie(0);
	ios_base::sync_with_stdio(0);
	
	while(cin>>N && N){
		rep(i,N)cin>>a[i];
		rep(i,N)cin>>b[i];
		sort(a,a+N,greater<int>());
		sort(b,b+N,greater<int>());
		int ans=-1;
		for(int i=0;i*2<N-1;i++){
			if(a[i*2] > b[i]){
				ans=i*2+1;
				break;
			}
		}
		if(ans==-1)cout<<"NA"<<endl;
		else cout<<ans<<endl;
	}
}