premise: Herbert has only visited Mauritania, Everett has only visited Equatorial Guinea, Raul has only visited Cambodia, Dustin has only visited São Tomé & Prícipe, Wallace has only visited Switzerland, Franklin has only visited Mali, Travis has only visited Oman, Bernard has only visited Netherlands, Leroy has only visited Cameroon, Vernon has only visited Tunisia, Gary has only visited Palestine, Marion has only visited Tanzania
hypothesis: Wallace didn't visit Switzerland