#include <bits/stdc++.h>
using namespace std;
//define
#define int long long
#define UNIQUE(v) v.erase(unique(all(v)), v.end());
#define ZIP(v) sort(all(v)),UNIQUE(v)
#define ADD(a, b) a = (a + b) % mod
#define SUB(a, b) a = (a+mod-b)%mod
#define MUL(a, b) a = (a * b) % mod
#define repi(i,m,n) for(int i = m;i < n;i++)
#define drep(i,n,m) for(int i = n;i >= m;i--)
#define rep(i,n) repi(i,0,n)
#define rrep(i,n) repi(i,1,n+1)
#define chmin(x,y) x = min(x,y)
#define chmax(x,y) x = max(x,y)
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(), v.rend()
#define dmp(x,y) make_pair(x,y)
#define pb(x) push_back(x)
#define fi first
#define se second
//template
template <typename T, typename U>
ostream &operator<<(ostream &os, const pair<T, U> &p){
  os << p.first << " " << p.second;return os;
}
template <typename T>
ostream &operator<<(ostream &os, const vector<T> &v){
  for (auto it = v.begin();it != v.end();++it){
    if (it != v.begin())os << " ";os << *it;
  }return os;
}
template<typename T, int SIZE>
int array_length(const T (&)[SIZE]){return SIZE;}
template<typename T, int N>
void print(const T (&a)[N], int s = N, int t = -1, bool f = true){
	if(t == -1){rep(i,s){if(i)cout << " ";cout << a[i];}}
	else repi(i,s,t){if(i!=s)cout << " ";cout << a[i];}
	if(f)cout << "\n";
}
template<typename T, int N1, int N2>
void print(const T (&a)[N1][N2], int h = N1, int w = N2){
	rep(i,h){rep(j,w){cout << a[i][j] << " \n"[j==w-1];}}
}
//typedef
typedef pair<int,int> P;
typedef pair<int, P> PP;
typedef pair<P, int> Pi;
typedef vector<int> vi;
typedef deque<int> dq;
const int inf = 1e9+7;
const int INF = 1e18+7;



bool prime[10000001], dp[10000001];
int a[30];
void eras(){
	fill(prime, prime+10000001, true);
	prime[0] = prime[1] = false;
	repi(i,2,10000001){
		if(prime[i])for(int j = 2;i*j <= 1000000;j++){
			prime[i*j] = false;
		}
	}
}

signed main(){
	eras();
	while(1){
		int n, x;
		cin >> n >> x;if(n == 0 and x == 0)break;
		rep(i,n)cin >> a[i];
		rep(i,x+1)dp[i] = false;
		dp[0] = true;
		rep(i,n){
			rep(j,x+1){
				if(j-a[i] < 0)continue;
				dp[j] = dp[j] | dp[j-a[i]];
			}
		}
		int ans = -1;
		drep(i,x,2){
			if(prime[i] and dp[i]){ans = i;break;}
		}
		cout << (ans == -1 ? "NA" : to_string(ans)) << endl;
	}
	return 0;
}





