premise: Jeffery has only visited Vietnam, Steven has only visited Sierra Leone, Bryan has only visited Bosnia & Herzegovinia, Bradley has only visited Philippines, Nelson has only visited Denmark, Kirk has only visited Haiti, Cecil has only visited Saint Lucia, Duane has only visited Sweden, Raul has only visited San Mmarino, Joseph has only visited Cabo, Joshua has only visited Laos, Jesus has only visited Uganda
hypothesis: Johnnie didn't visit Vietnam