Java简便解法，直接从中间开始取

import java.util.*;

public class Main{

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()){
            int n = sc.nextInt();
            int l = n/2;
            int r = n/2;

            while(l>2 && r<n-2){
                if(helper(l) && helper(r) && l+r==n) break;
                else {
                    l--;
                    r++;
                }
            }
            System.out.println(l);
            System.out.println(r);
        }
    }


    private static boolean helper(int n){
        if(n<=2) return false;
        for(int i=2;i<n;i++)
            if(n%i==0) return false;
        return true;
    }
}