// 基本テンプレート
 
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <string>
#include <cstring>
#include <deque>
#include <list>
#include <queue>
#include <stack>
#include <vector>
#include <utility>
#include <algorithm>
#include <map>
#include <set>
#include <complex>
#include <cmath>
#include <limits>
#include <cfloat>
#include <climits>
#include <ctime>
#include <cassert>
#include <numeric>
#include <fstream>
#include <functional>
using namespace std;
 
#define rep(i,a,n) for(int (i)=(a); (i)<(n); (i)++)
#define repq(i,a,n) for(int (i)=(a); (i)<=(n); (i)++)
#define repr(i,a,n) for(int (i)=(a); (i)>=(n); (i)--)
#define debug(...) fprintf(stderr, __VA_ARGS__)
#define int long long int
 
template<typename T> void chmax(T &a, T b) {a = max(a, b);}
template<typename T> void chmin(T &a, T b) {a = min(a, b);}
template<typename T> void chadd(T &a, T b) {a = a + b;}
 
typedef pair<int, int> pii;
typedef long long ll;
 
int dx[] = {0, 0, 1, -1};
int dy[] = {1, -1, 0, 0};
const ll INF = 1001001001001001LL;
const ll MOD = 1000000007LL;

const int MAXV = 1000010;
int N, X, dp[MAXV + 10], isPrime[MAXV + 10];
 
signed main() {
    fill(isPrime, isPrime + MAXV, true);
    isPrime[0] = isPrime[1] = false;
    for(int k=2; k<=MAXV; k++) {
        if(isPrime[k]) {
            for(int i=k+k; i<=MAXV; i+=k) {
                isPrime[i] = false;
            }
        }
    }

    while(cin >> N >> X, N) {
        memset(dp, 0, sizeof(dp));
        dp[0] = true;
        for(int i=0; i<N; i++) {
            int val; cin >> val;
            for(int p=0; p<=X-val; p++) {
                dp[p+val] |= dp[p];
            }
        }

        int ans = -1;
        for(int i=2; i<=MAXV; i++) {
            if(isPrime[i] and dp[i]) {
                ans = max(ans, i);
            }
        }

        if(ans < 0) cout << "NA" << endl;
        else cout << ans << endl;
    }
    return 0;
}
