premise: Joseph has only visited Rwanda, Billy has only visited Palau, Darryl has only visited Kosovo, Isaac has only visited Moldova, Gregory has only visited Belize, Joe has only visited Vatican City, Sam has only visited Israel, Duane has only visited Bhutan, Armando has only visited Tuvalu, Anthony has only visited Switzerland, Milton has only visited Liberia, Andrew has only visited Norway
hypothesis: Billy didn't visit Malaysia