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

#define pb push_back
#define fi first
#define se second
#define all(x) (x).begin(), (x).end()
#define Sz(x) (int)(x).size()
#define bit(x) (1ll << (x))
using ll = long long;
using db = double;
using ull = unsigned long long;
using pii = pair<int, int>;
using vi = vector<int>;
using vii = vector<vi>;
using vl = vector<ll>;
using vll = vector<vl>;
using vs = vector<string>;
using vd = vector<db>;
mt19937 mrand(time(0));

void solve(void)
{
	int n;
	cin >> n;
	vi vis(n + 2);
	vector<array<int, 2>> ans;
	for (int i = 2; i <= n; i++) if (!vis[i])
	{
		int bd = 0;
		for (int d = 2; d * d <= i; d++)
		{
			bd = d;
			if (i % d == 0 && !vis[i / d])
			{
				ans.pb({i, i / d});
				vis[i] = vis[i / d] = 1;
				break;
			}
		}

		if (!vis[i])
		{
			for (int d = bd; d >= 2; d--)
			{
				// cerr << i << " " << d << "\n";
				if (i % d == 0 && !vis[d])
				{
					ans.pb({i, d});
					vis[i] = vis[d] = 1;
					break;
				}			
			}
		}

	}
	// cerr << "GG\n";

	int m = Sz(ans);
	cout << m << " \n"[m == 0];
	for (int i = 0; i < m; i++)
		cout << ans[i][0] << " " << ans[i][1] << " \n"[i == m - 1];
}

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);

	// cout << fixed << setprecision(10);

	int T = 1;
	cin >> T;
	for (int i = 1; i <= T; i++)
	solve();

	return 0;
}