#include <bits/stdc++.h>

using namespace std;

void solve(int cs) {
  int n;
  cin >> n;
  vector<int> a(n);
  iota(a.begin(), a.end(), 1);
  for (int i = 1; i < n; i += 2) {
    if (a[i] == i + 1) swap(a[i], a[i - 1]);
  }
  if (a.back() == n) swap(a.back(), a[n - 2]);
  for (int i = 0; i < n; i++) {
    cout << a[i] << " \n"[i + 1 == n];
  }
}

int32_t main() {
  cin.tie(0) -> sync_with_stdio(0);
  int t = 1;
  cin >> t;
  for (int i = 1; i <= t; i++) {
    solve(i);
  }
  return 0;
}