#if __has_include("../stdc++.h")
	#include "../stdc++.h"
#else
	#include <bits/stdc++.h>
#endif

template <typename T>
std::istream &operator>>(std::istream &in, std::vector<T> &v)
{
    for (T &x : v)
        in >> x;
    return in;
}

template <typename T>
std::ostream &operator<<(std::ostream &out, const std::vector<T> &v)
{
    for (std::size_t i = 0; i < v.size(); ++i)
        out << v[i] << (i + 1 == v.size() ? "" : " ");
    return out;
}

inline void yes() { std::cout << "Yes\n"; }
inline void no()  { std::cout << "No\n";  }

using namespace std;

void solve()
{
    int n;
    cin >> n;
    if (n == 3) {
        cout << "2 3 1\n";
        return;
    }

    for (int i = 1; i <= n; i+= 2) {
        if (i == n - 2) {
            cout << i << " " << n << " " << i + 1;
            break;
        }
        else {
            cout << i + 1<< " " << i << " ";
        }
    }
    cout << '\n';
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int t = 1;
    cin >> t;
    while (t--)
        solve();
    return 0;
}