This short story by Isaac Asimov was first published in October of 1961. Asimov published it in a science fiction magazine by the name of "The Magazine of Fantasy and Science Fiction."
In the story, three men are talking about a war with another planet (Deneb) that their society has just won. They are discussing the role that a supercomputer (Mulitvac) has allegedly played in winning the war for them. As it turns out, however, the man who was entering the data into the computer didn't believe the data and was instead just flipping a coin to determine what should be done.