Question: Seven members of a group of nineteen people dislike the New Democratic Party (NDP), ten dislike the Liberals, eleven dislike the Conservatives, and six dislike the Canadian Alliance. Five of the group dislike both the Liberals and the New Democratic Party, five dislike both the NDP and the Conservatives, six dislike the Liberals and Conservatives, three dislike the New Democratic and Canadian Alliance parties, four dislike the Liberals and the Alliance, and five dislike the Conservatives and the Alliance. Three people dislike the Conservatives, Liberals, and the NDP, while two dislike the Liberals, NDP, and Alliance; three dislike the Conservatives, New 6.1 The Principle of Inclusion-Exclusion 195 Democrats, and Alliance; and four dislike the Conservatives, Liberals, and Alliance. Two people dislike all four parties. How many members of the group like all four parties?