#include<cstdio>
#include<iostream>
#include<algorithm>
using namespace std;

int n;
int a[40000],b[40000];

int main(){
  while(scanf("%d",&n),n){
    for(int i=0;i<n;i++)scanf("%d",&a[i]);
    for(int i=0;i<n;i++)scanf("%d",&b[i]);

    sort(a,a+n,greater<int>());
    sort(b,b+n,greater<int>());

    n >>=1;
    int i;
    for(i=0;i<n;i++){
      if(a[i<<1]>b[i]){
	cout << (i<<1)+1 << endl;
	break;
      }
    }
    if(i==n)cout << "NA\n";
  }
}