#include <bits/stdc++.h>
using namespace std;
#define mem(x) memset(x, 0, sizeof x)
#define all(x) (x).begin(), (x).end()
#define endl "\n"
typedef long long ll;
inline ll rint() { ll x = 0, f = 1; char c = getchar(); while (c<'0' || c>'9') { if (c == '-')f = -1; c = getchar(); }while (c >= '0'&&c <= '9') { x = x * 10 + c - '0'; c = getchar(); }return x * f; }
inline ll gcd(ll a, ll b) { return (b) ? gcd(b, a%b) : a; }
inline ll lcm(ll a, ll b) { return a / gcd(a, b)*b; }
inline ll pow(ll a, ll b, ll q) { ll rtn = 1; while (b) { if (b & 1) rtn = rtn * a%q; a = a * a%q; b >>= 1; } return rtn; }
inline ll mysqrt(ll n) { ll x = sqrt(n); while (x*x < n) x++; while (x*x > n) x--; return x; }

void solve() {
  ll n=rint();
  vector<pair<ll,ll>> v;
  vector<ll> lishu = {2,3,5,22,448};
  for(int i=4;i<=n-1;i++) if(find(all(lishu),i)==lishu.end()) v.emplace_back(i,n);
  while(*lishu.rbegin()>=n) lishu.pop_back();
  lishu.push_back(n);
  for(int i=lishu.size()-1;i>=1;i--) v.emplace_back(lishu[i],lishu[i-1]),v.emplace_back(lishu[i],lishu[i-1]);
  cout<<v.size()<<endl;
  for(auto i:v) cout<<i.first<<" "<<i.second<<endl;
}

int main() {
  ll t=rint(); while(t--) solve();
//  solve();
  return 0;
}