Problem Description

Transform number A into number B using the minimum number of operations. Available operations: add 1, multiply by 2, subtract 3. Find the minimum steps required to reach B from A.

Input Format

Two integers A and B on separate lines.

Output Format

Minimum number of operations needed to transform A into B, or -1 if impossible.

Constraints

• 1 ≤ A, B ≤ 1000

• Operations: +1, ×2, -3

• Cannot go below 1 during transformation

• If B is unreachable, return -1

• Use BFS for optimal solution

Sample Input/Output

2
10

3

Explanation

Transform 2 → 10: Step 1: 2×2=4, Step 2: 4×2=8, Step 3: 8+1=9, Step 4: 9+1=10. Wait, that's 4 steps. Better: 2+1=3, 3×2=6, 6+1=7, 7+1=8, 8+1=9, 9+1=10. Actually optimal: 2×2=4, 4+1=5, 5×2=10. That's 3 steps.