premise: Robert has only visited Vietnam, Paul has only visited Mongolia, Steven has only visited Cambodia, Marion has only visited Slovakia, Ben has only visited Jamaica, Gilbert has only visited Saint Kitts & Nevis, Mike has only visited Republic of the Congo, Jeff has only visited Somalia, Tim has only visited North Korea, Hector has only visited Sri Lanka, Dustin has only visited Netherlands, Peter has only visited Mozambique
hypothesis: Hector didn't visit United Kingdom