premise: Walter has only visited El Salvador, Andrew has only visited Suriname, Max has only visited Vanuatu, Jorge has only visited Greece, Ricky has only visited Gabon, Kirk has only visited The Bahamas, Joel has only visited Cambodia, Chad has only visited Israel, Phillip has only visited Belgium, Troy has only visited Sierra Leone, Mike has only visited Federated States of Micronesia
hypothesis: Walter didn't visit Republic of the Congo