#include <math.h>
#include <stack>
#include <stdio.h>
#include <iostream>
#include <vector>
#include <iomanip>
#include <string.h>
#include <algorithm>
using namespace std;
#define LL long long
const int N = 1e5 + 10;
const int INF = 0x3f3f3f3f;
int main()
{
    int n;
    cin >> n;
    int sum = 0;
    for(int i = 3 ; i + 2 <= n ; i += 2)
    {
        int flag = 1;
        for(int j = 2; j*j <= i ; j++)
        {
            if(i%j == 0)
            {
                flag = 0;
                break;
            }
        }
        if(flag == 0)
        {
            sum++;
            cout << i << " " << i + 2 << endl;
        }
    }
    if(sum==0)
    {
        cout << "empty\n";
    }
    return 0;
}```