#include <bits/stdc++.h>   using namespace std;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     long long int t, n, i, x;     cin >> t;     while (t--) {       cin >> n;       i = n - 1;       x = n;       cout <<  2  << endl;       while (i != 0) {         cout << i <<     << x << endl;         x = ceil((i + x) / 2.0);         i--;       }     }     return 0;   }   