You will be given a definition of a task first, then some input of the task.
Given a passage and a question, find the answer to the question based on the passage. The answer should consist of only one word that lies in the span of only one of the sentences in the passage.

Paragraph: McClellan had halted Lee 's invasion of Maryland , but Lee was able to withdraw his army back to Virginia without interference from the cautious McClellan . McClellan 's refusal to pursue Lee 's army led to his removal from command by President Abraham Lincoln in November . Although the battle was tactically inconclusive , the Confederate troops had withdrawn first from the battlefield , making it a Union strategic victory . It was a sufficiently significant victory to give Lincoln the confidence to announce his Emancipation Proclamation , which discouraged the British and French governments from pursuing any potential plans to recognize the Confederacy .
Question: who won the civil war battle of antietam

Output:
Union