premise: Clayton has only visited South Korea, Jason has only visited Guyana, Virgil has only visited Zimbabwe, Mario has only visited Luxembourg, Nathaniel has only visited Estonia, Herman has only visited Chile, Jeffery has only visited Marshall Islands, Edgar has only visited Bhutan, Benjamin has only visited Dominica, Greg has only visited North Korea, Shawn has only visited Ukraine, Andrew has only visited Philippines
hypothesis: Kenneth didn't visit North Korea