Conversation so far:
How long was Harry S. Truman vice president?
Harry Truman had been vice president for 82 days when President Roosevelt died on April 12, 1945.
When did President Franklin D. Roosevelt die?
President Roosevelt died on April 12, 1945.

Question: How did Truman react to that?
Self-contained rewrite: How did Harry S. Truman react to President Roosevelt's death?