premise: Jessie has only visited Dominican Republic, Melvin has only visited Côte D'ivore, Leroy has only visited Solomon Islands, Jerry has only visited Djibouti, Gordon has only visited Switzerland, Christian has only visited Comoros, Terrance has only visited Kiribati, Ted has only visited Palestine, Keith has only visited Equatorial Guinea, Martin has only visited Lesotho, Jonathan has only visited Nauru, David has only visited Uruguay
hypothesis: Keith didn't visit Mauritius