Go: package main

import (
	"bufio"
	"os"
	"strings"
	"strconv"
	"fmt"
	)

var scanner = bufio.NewScanner(os.Stdin)

func main() {
	for scanner.Scan() {
		buf := strings.Split(scanner.Text(), " ")
		n, _ := strconv.Atoi(buf[0])
		x, _ := strconv.Atoi(buf[1])
		prime_table := make([]int, 1000001)
		prime_table[0] = -1
		prime_table[1] = -1
		for i := 2; i < 1000001; i++ {
			if prime_table[i] != -1 {
				prime_table[i] = 1
				for j := 2*i; j < 1000001; j += i {
					prime_table[j] = -1 // -1 means "not prime"
				}
			}
		}
		dp := make([]int, x+1)
		dp[0] = 1
		menu := make([]int, n)
		for i := 0; i < n; i++ {
			scanner.Scan()
			menu[i], _ = strconv.Atoi(scanner.Text())
		}
		for i := 0; i < n; i++ {
			for j := 0; j <= x; j++ {
				if menu[i] <= j && dp[j-menu[i]] != 0 {
					// log.Println(dp)
					dp[j] = 1
				}
			}
		}
		flag := true
		for j := x; j >= 0; j-- {
			if prime_table[j] == 1 && dp[j] == 1 {
				flag = false
				fmt.Println(j)
				break
			}
		}
		if flag {
			fmt.Println("NA")
		}
	}
}

C++: #include <stdio.h>

int ans = -1;
char visited[1000001], isprime[1000001];
int price[30];
int n, x;

void eratos(int m)
{
	int i, j;
	for(i=2; i<=m; ++i)
		isprime[i] = 1;
	isprime[0] = isprime[1] = 0;
	
	for(i=2; i*i<=m; ++i){
		if(isprime[i]){
			for(j=i*2; j<=m; j+=i)
				isprime[j] = 0;
		}
	}
}

void search(int c)
{
	int i;
	if(visited[c])
		return;
	visited[c] = 1;
	
	if(ans < c && isprime[c])
		ans = c;
	
	for(i=0; i<n; ++i){
		if(c+price[i] <= x)
			search(c+price[i]);
	}
}

int main(void)
{
	eratos(1000000);
	while(scanf("%d%d", &n, &x), n){
		int i;
		for(i=0; i<n; ++i)
			scanf("%d", &price[i]);
		
		ans = -1;
		for(i=0; i<=x; ++i)
			visited[i] = 0;

		search(0);
		if(ans == -1)
			puts("NA");
		else
			printf("%d\n", ans);
	}
	return 0;
}

C++: #include <stdio.h>

int n,m[30];
/*
bool prime[1000000];
*/
bool c[1000000];

void saiki(int total){
	int i;
	if(total<=0){
		return;
	}
	
	for( i=0 ; i<n ; i++){
		total-=m[i];
		if(c[total]==1)continue;
		if(total>=0){
			c[total]=1;
		}
		saiki(total);
	}
}

int check(int prime){
	int flg=0,i;
	if(prime%2==0)return 0;
	for(i=2;i<prime;i++){
		if(prime%i==0){
			flg=1;
		}
	}
	if(flg==1)return 0;
	return 1;
}

int main(void)
{
	int i,j;
	//f
	/*
	prime[0]=1;
	prime[1]=1;
	for(i=3;i<1000000;i++){
		if(i%2==0){
			prime[i]=1;
		}
	}
	for(i=3;i<1000000;i++){
		if(prime[i]==0){
			for(j=(i+i);j<1000000;j+=i){
				prime[j]=1;
			}
		}
	}
	*/
	//
	while(1){
		int x;
		int flg=0;
		scanf("%d%d",&n,&x);
		if(n==0)break;
		
		for(i=0;i<n;i++){
			scanf("%d",&m[i]);
		}
		saiki(x);
		//
		for(i=0;i<x;i++){
			
			if(c[i]==1 && check(x-i)){
				flg=1;
				break;
			}
		}
		if(flg==1){
			printf("%d\n",x-i);
		}
		else puts("NA");
		for(i=0;i<1000000;i++){
			c[i]=0;
		}
		//
	}
	
	
	return 0;
}

C++: #include<iostream>
#include<algorithm>
#define rep(i,n) for(int i=0;i<n;i++)
#define MC 1000001
using namespace std;
int p[MC],V[MC]; int n,x,c[35],ans;
void rec(int a){
	rep(i,n)if(a+c[i]<x&&!V[a+c[i]])V[a+c[i]]=1,rec(a+c[i]);
}
int main(){
	for(int i=2;i*i<MC;i++)if(!p[i])for(int j=i+i;j<MC;j+=i)p[j]=1;
	p[0]=p[1]=1;
	while(cin>>n>>x,n){
		rep(i,n)cin>>c[i]; sort(c,c+n);
		fill(V,V+x,0); rec(0);
		for(ans=x;ans>=c[0];ans--)if(!p[ans]&&V[ans])break;
		if(ans<c[0])cout<<"NA"<<endl;
		else cout<<ans<<endl;
	}
	return 0;
}

C++: #include<iostream>
#include<algorithm>
using namespace std;
int main(){
  //ツ素ツ青板青カツ青ャ
  const int NUM = 1000000;
  bool prime[NUM];
  prime[0] = false;
  prime[1] = false;
  for(int i=2;i<NUM;i++)
    prime[i] = true;
  for(int i=2;i*i<NUM;i++)
    for(int k=2;i*k<NUM;k++)
      prime[i*k]=false;

  while(true){
    int n,x;
    cin>>n>>x;
    if(!n&&!x)break;
    int menu[n];
    for(int i=0;i<n;i++){
      cin>>menu[i];
    }
    sort(menu,menu+n);
    int p = -1;
    bool money[x+1];
    money[0] = true;
    for(int i=1;i<x+1;i++){
      money[i] = false;
      for(int j=0;j<n;j++){
	if(i>=menu[j]&&money[i-menu[j]]){
	  money[i] = true;
	  break;
	}
      }
      if(money[i]&&prime[i])p=i;
    }
    if(p==-1)cout<<"NA"<<endl;
    else cout<<p<<endl;
  }
  return 0;
}

C++: #include<iostream>
#include<string.h>
#include<cstdio>
#include<algorithm>
#include<stack>
#include<queue>
#include<vector>
#include<cmath>
#include<utility>
#define ll long long int
#define ld long double
#define INF 1000000000
#define EPS 0.0000000001
#define rep(i,n) for(i=0;i<n;i++)
using namespace std;
typedef pair<int, int> P;

string str;

int main()
{
  bool prime[1000005]={};//true   
  int n,x,i,j,k;

  rep(i,1000005)
    prime[i]=true;
  for(i=2;i<1000005;i++){
    if(prime[i])
      for(j=2;i*j<1000005;j++)
	prime[i*j]=false;
  }

  while(1){
    int price[30]={};
    int cost[1000005]={};
    cin>>n>>x;
    if(n==0 && x==0)break;
    rep(i,n){
      cin>>price[i];
      cost[price[i]]++;
    }

    rep(i,x)
      if(cost[i])
	rep(j,n)
	  cost[i+price[j]]++;


    for(i=x;i>0;i--)
      if(cost[i]>0 && prime[i])break;

    if(i)
      cout<<i<<endl;
    else
      cout<<"NA"<<endl;
  }
}

C++: #include<iostream>
#include<string>
#include<cstdio>
#include<algorithm>
#include<stack>
#include<queue>
#include<vector>
#include<cmath>
#include<utility>
#include<set>
#include<complex>
#define vi vector<int>
#define vvi vector<vector<int> >
#define ll long long int
#define vl vector<ll>
#define vvl vector<vector<ll>>
#define vb vector<bool>
#define vc vector<char>
#define vs vector<string>
#define ld long double
#define INF 1e9
#define EPS 0.0000000001
#define rep(i,n) for(int i=0;i<n;i++)
#define CC puts("-------ok--------");
#define all(in) in.begin(), in.end()
#define bv vector<bool>
using namespace std;
typedef pair<int, int> PI;
#define MAX 1000009
/*void dfs(int num){
    if(flag) return;
    if(ans==num){flag=true;return;}
    if(num>ans){memo[num]=false;return;}
    else rep(i,n){
        cout<<num<<endl;
      if(num+v[i]<=ans&&memo[num+v[i]])dfs(num+v[i]);
    }
    memo[num]=false;
    return;
}*/
int main(){
    vector<bool>check(MAX+1);  //index number will be checked
    rep(i, MAX+1)check[i] = true;
    vector<int>Primenumber(MAX+1,0); //Primearray
    int counter =0;                  //Primearray counter;
    for(int i = 2; i<MAX+1;i++){
        if(check[i]){
            for(int j = 2;i*j<MAX;j++)
                check[i*j] = false;//?´???°??????Primearray???????´??????????????????°?????¨???false???
            Primenumber[counter] = i;
            counter++;
        }
    }
    int m,n,ans; bool flag;
    while(cin>>n>>m,n+m){
        vi v;
        int temp;
        flag=false;
        rep(i,n){cin>>temp; v.push_back(temp);}
        for(int i=m;i>=2;i--){
            if(check[i]){
                ans=i;break;}
        }
        bool array[MAX]; rep(i,MAX)array[i]=false;
        rep(i,n)array[v[i]]=true;
        for(int i=2;i<=MAX;i++) {
            if(array[i])rep(j,n)if(i+v[j]<=MAX)array[i+v[j]]=true;
            if(array[ans])break;
        }
        if(array[ans]) cout<<ans<<endl;
        else cout<<"NA"<<endl;
    }
}