package main

import (
	"fmt"
	"strconv"
)

func gcd(a, b int64) int64 {
	for b != 0 {
		a, b = b, a%b
	}
	return a
}

func main() {
	var x, y int64
	if _, err := fmt.Scan(&x, &y); err != nil {
		return
	}

	if gcd(x, y) != 1 {
		fmt.Println("Impossible")
		return
	}

	var result string
	for x > 0 && y > 0 {
		if x > y {
			count := x / y
			if y == 1 {
				count--
			}
			result += strconv.FormatInt(count, 10) + "A"
			x %= y
		} else if y > x {
			count := y / x
			if x == 1 {
				count--
			}
			result += strconv.FormatInt(count, 10) + "B"
			y %= x
		} else {
			break
		}
	}

	fmt.Println(result)
}