premise: Jeffery has only visited Timor-Leste, Nicholas has only visited Niger, Lee has only visited Sri Lanka, Terrance has only visited Uganda, Salvador has only visited Venezuela, Lance has only visited Suriname, Warren has only visited Angola, Angel has only visited Zambia, Aaron has only visited Guatemala, Fred has only visited Romania, Dan has only visited Mauritania, Alberto has only visited Senegal
hypothesis: Fred didn't visit Romania