Which US president served the longest term?
Franklin D. Roosevelt is the US president who served the longest term. He was elected for four terms and served a total of 12 years in office from 1933 to 1945. Roosevelt died in office on 1945, during his fourth term.
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### Instruction:
Which US president served the longest term?

### Response:
Franklin D. Roosevelt is the US president who served the longest term. He was elected for four terms and served a total of 12 years in office from 1933 to 1945. Roosevelt died in office on 1945, during his fourth term.