java问题，实在不会写，希望有人帮助

Question

noi网址:

OpenJudge - NOI http://noi.openjudge.cn/ch0105/30/%EF%BC%8Chttp://noi.openjudge.cn/ch0112/10/

,

Answer 1

public class test{
    public static int isprime(int n)
    {
        for(int i=2;i<=n;i++)
              if(n%i==0)
                  return 0;
        return 1;
    }
    public static void main(String[] args) {        
        Scanner input =new Scanner(System.in);
        int n = input.nextInt();
        for(int i=2;i<=n-2;i++)
        {
                if(isprime(i) && isprime(i+2))
                    System.out.println(i+","+i+2);
        }
}