```go
package main

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

func main() {
	var q int
	reader := bufio.NewReader(os.Stdin)
	fmt.Fscan(reader, &q)

	for ; q > 0; q-- {
		var s, t string
		fmt.Fscan(reader, &s)
		fmt.Fscan(reader, &t)

		if t == "a" {
			fmt.Println(1)
		} else if strings.Contains(t, "a") {
			fmt.Println(-1)
		} else {
			fmt.Println(int64(1) << len(s))
		}
	}
}
```