func_code_string: #include <bits/stdc++.h>   using namespace std;   vector<pair<long long, long long> > vp;   vector<long long> v;   set<long long> st;   long long ara[500005];   map<string, long long> mp;   long long Set(long long N, long long pos) { return N = N | (1LL << pos); }   long long reset(long long N, long long pos) { return N = N & ~(1LL << pos); }   bool check(long long N, long long pos) { return (bool)(N & (1LL << pos)); }   vector<long long> e, o;   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     long long t, n, i, j, p;     cin >> t;     while (t--) {       cin >> n;       v.clear(), vp.clear();       for (i = 0; i < n; i++) v.push_back(i + 1);       long long a = n;       for (i = n - 1; i >= 0; i--) {         vp.push_back({a, i});         a = (a + i + 1) / 2;       }       cout << 2 << endl;       for (i = 0; i < n - 1; i++)         cout << vp[i].first <<     << vp[i].second << endl;     }   }   