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

int main()
{
    int T;
    cin>>T;
    while(T--)
    {
        int N;
        cin>>N;
        vector<int>v1;
        
            for(int i=1; i<N; i+=2)
            {
                v1.push_back(i+1);
                v1.push_back(i);
            }
            if(N%2==0)
            {
                for(auto x:v1)
                {
                    cout<<x<<" ";
                }
            }
            else
            {
                v1.push_back(N);
                swap(v1[N-2],v1[N-1]);

                for(auto x:v1)
                {
                    cout<<x<<" ";
                }
            }
    }
}