Hanzo's written the code that you need to use, but I want to add this for your own understanding.
The reason it was printing a 0 is in line 11. When you write "... THEN PRINT A==4", it's not making the assignment that you want it to. It's actually evaluating "A==4", deciding that the answer is FALSE (0), and PRINTing that answer.
1そうだね プレイ済み