#include <bits/stdc++.h>
using namespace std;

#define int long long
#define ld long double
#define cinv(v) for(auto &i:v) cin >> i;
#define vi vector<int>
#define vii vector<ll>
#define mod 1000000000
#define coutv(v) for(auto e:v) cout << e << ' ';
#define srt(v) sort(v.begin(),v.end())
#define rsrt(v) sort(v.rbegin(),v.rend())
#define yes cout<<"Yes\n"
#define no cout<<"No\n"
#define endl '\n'
#define saklan ios::sync_with_stdio(0); cin.tie(0);


//or (v[1] == 2 and v[n] == 1)
void solve() {
    int t = 1;
    cin >> t;
    while(t--) {
        int n; cin >> n;
        int odd = 1, even = 4;
        vi v;
        v.push_back(2);
        if(n==2){
            cout << "2 1" << endl;
        }else if(n==3) cout << "2 3 1" << endl;
        else{

            for(int i = 1; i < n; i++){
                if(i%2){
                    v.push_back(odd);
                    odd+=2;
                }else{
                    v.push_back(even);
                    even+=2;
                }

            }
            if(n%2){
                v[n-1] = n;
                swap(v[n-1],v[n-2]);
            }
            for(auto val : v) cout << val << " ";
            cout << endl;
        }



//        for(auto val : v) cout << val << " ";
//        cout << endl << "______" << endl;






//        while(cpy--){
//            if(c%2==0){
//                cout << even << " ";
//                even+=2;
//            }else{
//                cout << odd << " ";
//                odd+=2;
//            }
//            c++;
//        }
//        cout << endl;

    }
}


int32_t main() {

    solve();
    return 0;
}