#include <bits/stdc++.h>
using namespace std;

#define SZ(a) (int)a.size()
#define ALL(a) a.begin(), a.end()
#define FOR(i, a, b) for (int i = (a); i<(b); ++i)
#define RFOR(i, b, a) for (int i = (b)-1; i>=(a); --i)
#define MP make_pair
#define PB push_back
#define F first
#define S second
#define FILL(a, b) memset(a, b, sizeof(a))

typedef long long LL;
typedef pair<int, int> PII;
typedef vector<int> VI;

const int N = 100447;
int d[N];
VI pr;
bool used[N];

void solve()
{
	int n;
	cin >> n;
	vector<PII> ans;
	RFOR (i, n + 1, 2)
	{
		if (pr[i])
		{
			VI v;
			for (int j = i; j <= n; j += i)
				if (!used[j]) v.PB(j);
			if ((SZ(v) & 1) && SZ(v) > 1)
			{
				swap(v[1], v.back());
				v.pop_back();
			}
			FOR (j, 0, SZ(v) / 2)
			{
				used[v[j * 2]] = 1;
				used[v[j * 2 + 1]] = 1;
				ans.PB({v[j * 2], v[j * 2 + 1]});
			}
		}
	}
	FOR (i, 0, n + 1)
		used[i] = 0;
	cout << SZ(ans);
	FOR (i, 0, SZ(ans)) cout << ' ' << ans[i].F << ' ' << ans[i].S;
	cout << '\n';
}

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	
	pr.assign(N, 1);
	FOR (i, 2, N)
	{
		if (pr[i])
		{
			d[i] = i;
			for (int j = i * 2; j < N; j += i)
			{
				if (d[j] == 0)
					d[j] = i;
				pr[j] = 0;
			}
		}
	}
	
	int t;
	cin >> t;
	while (t--)
	{
		solve();
	}
	
	return 0;
}