A

#include <bits/stdc++.h>

using namespace std;

#define _test   int _TEST; cin>>_TEST; while(_TEST--)

int main()
{
    _test
    {
        int n;
        cin>>n;

        if(n%2)
        {
            cout<<"NO\n";
            continue;
        }

        char ch = 'A';
        string ans = "";

        while(n)
        {
            ans += ch;
            ans += ch;
            ch++;
            n -= 2;
        }

        cout<<"YES\n"<<ans<<"\n";
    }
}