```go
package main

import (
	"bufio"
	"fmt"
	"os"
)

func main() {
	in := bufio.NewReader(os.Stdin)
	out := bufio.NewWriter(os.Stdout)
	defer out.Flush()

	var t int
	fmt.Fscan(in, &t)
	for ; t > 0; t-- {
		var n int
		fmt.Fscan(in, &n)

		if n == 1 {
			fmt.Fprintln(out, "NO")
			continue
		}

		fmt.Fprintln(out, "YES")
		s := make([]byte, n+1)
		for i := 0; i < n+1; i++ {
			if i%2 == 0 {
				s[i] = 'A'
			} else {
				s[i] = 'B'
			}
		}
		fmt.Fprintln(out, string(s))
	}
}
```