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 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=3;i<prime;i+=2){
		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;
		}
		for(;;);
		//
	}
	
	
	return 0;
}

C++: #include <stdio.h>

int n,m[50];
bool prime[1000000],c[1000000];

void saiki(int total){
	int i;
	
	c[total]=1;
	
	for( i=total ; i>=0 ; i--){
		if(c[i]==1){
			for(int j=0;j<n;j++){
				if(i-m[j]>=0){
					c[i-m[j]]=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+=2){
		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 && prime[x-i]==0){
				flg=1;
				break;
			}
		}
		if(flg==1){
			printf("%d\n",x-i);
		}
		else puts("NA");
		for(i=0;i<1000000;i++){
			c[i]=0;
		}
		for(i=0;i<50;i++){
			m[i]=0;
		}
		//
	}
	
	return 0;
}

C++: #include <iostream>
#define N 1000000 
using  namespace std;

int main(void){
	bool isprime[N+1];
	for(int i=0;i<=N;i++)
		isprime[i]=true;
	isprime[0]=isprime[1]=false;
	for(int i=2;i<=N;i++)
		if(isprime[i])
			for(int j=2*i;j<=N;j+=i)
				isprime[j]=false;
	bool budget[N+1];
	int n,m;
	while(cin >> n>>m,n|m){
		for(int i=0;i<=m;i++)
			budget[i]=false;
		int tmp;
		budget[0]=true;
		for(int i=0;i<n;i++){
			cin >> tmp;
			for(int j=0;j<=m;j++)
				if(budget[j]&&(j+tpm)<=m)
					budget[j+tmp]=true;
		}
		int MAX=0;
		for(int i=m;i>0;i--){
			if(budget[i]&isprime[i]){
				MAX=i;break;
			}
		}
		if(MAX)
			cout << MAX << endl;
		else
			cout << "NA" << endl;
	}
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
bool sosu[1000005]={0};
bool check[1000005];
main(){
  int n,k;
  int shop;
  sosu[1]=1;
  for(int i=2;i<(int)sqrt(1000005);i++){
    if(sosu[i]==0){
      for(int j=i;j<1000005;j+=i){
	sosu[j]=true;
      }
    }
  }
  while(1){
    bool a=true;
    cin>>n>>k;
    if(n==0&&k==0)break;
    memset(check,false,sizeof(check));
    for(int i=1;i<=n;i++){
      scanf("%d",&shop);
      check[shop]=true;
      for(int j=shop;j<=k;j++){
	if(check[j-shop]==true){
	  check[j]=true;
	}
      }  
    }
    for(int i=k;i>0;i--){
      if(sosu[i]==false&&check[i]==true){
	cout<<i<<endl;
	i=0;
	a=false;
      } 
    }
    if(a){
      cout<<"NA"<<endl;
    }
  }
}

C++: #include <stdio.h>
#include <map>

using namespace std;


int *ms;
int n, m;

bool *dp;
bool *data;

bool search(int m){
	if(m == 0) return true;
	else if(m < 0) return false;
	else if(dp[m]) return data[m];

	for(int i=0;i<n;i++){
		if(search(m-ms[i])){
			return dp[m] = data[m] = true; 
		}
	}
	
	dp[m] = true;
	return data[m]=false;
}

int isprime(int p){
	if(p%2==0) return 0;
	for(int i=3;i*i<p;i++){
		if(p%i==0) return 0;
	}
	return 1;
}

int main(){
	while(1){
		scanf("%d%d", &n,&m);
		
		if(n==0) break;
		
		int i;
		dp = new bool[m+1];
		data = new bool[m+1];
		for(i=0;i<=m;i++) dp[i] = false;
		
		ms = new int[n];
		for(i=0;i<n;i++) scanf("%d", ms+i);
		
		int flag = 1;
		for(i=m;i>=0;i--){
			if(search(i) && isprime(i)){
				printf("%d\n", i);
				flag = 0;
				break;
			}
		}
		if(flag) puts("NA");
	}
}

C++: #include <iostream>
#include <fstream>
#include <sstream>
#include <iomanip>
#include <complex>
#include <string>
#include <vector>
#include <list>
#include <deque>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <bitset>
#include <functional>
#include <utility>
#include <algorithm>
#include <numeric>
#include <typeinfo>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <ctime>

using namespace std;

#define dump(n) cout<<"# "<<#n<<"="<<(n)<<endl
#define debug(n) cout<<__FILE__<<","<<__LINE__<<": #"<<#n<<"="<<(n)<<endl
#define repi(i,a,b) for(int i=int(a);i<int(b);i++)
#define rep(i,n) repi(i,0,n)
#define iter(c) __typeof((c).begin())
#define foreach(i,c) for(iter(c) i=(c).begin();i!=(c).end();i++)
#define allof(c) (c).begin(),(c).end()
#define mp make_pair

typedef unsigned int uint;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<string> vs;
typedef pair<int,int> pii;

int main()
{
	vi isprime(1000001,1);
	isprime[0]=isprime[1]=0;
	repi(i,2,isprime.size())
		if(isprime[i])
			for(int j=i+i;j<isprime.size();j+=i)
				isprime[j]=0;
	for(int n,x;cin>>n>>x,n|x;){
		vi price(n);
		rep(i,n)
			cin>>price[i];
		vi dp(x+1);
		dp[0]=1;
		rep(i,n)
			repi(j,price[i],dp.size())
				if(dp[j-price[i]])
					dp[j]=1;
		bool flg=false;
		rep(i,dp.size())
			if(dp[x-i] && isprime[x-i]){
				printf("%d\n",x-i);
				flg=true;
				break;
			}
		if(!flg)
			puts("NA");
	}
	
	return 0;
}