Question:

Step 1: Analyze the provided information. The question is an integer-type question, which requires a single integer value as the answer. The "Original Solution" directly states "Answer: 4." without providing any intermediate mathematical steps or derivation. Step 2: Extract the final answer. Since the original solution directly presents the final result without any calculation, we accept the stated value as the intended final answer to the problem. Step 3: State the final answer. The final integer answer provided in the solution is $4$. The final answer is $\boxed{4}$.