Americans sent over a hundred million Fathers Day messages on Sunday, the National Security Agency reported today. The hundred-million number, while robust, falls short of the hundred and twenty million Mothers Day messages collected by the N.S.A. in May. The difference between the two figures is not surprising, said N.S.A. director General Keith B. Alexander. He added, On the whole, mothers take Mothers Day more seriouslyif the e-mails we read by mothers whose children forgot are any indication. General Alexander said that the agency collected in the neighborhood of two to three million such e-mails from angry mothers this year. The N.S.A. director added that the agency had not foiled any terror plots over the weekend but did uncover between thirty and forty thousand extramarital relationships. 