Chesterton Weekly 9/30/20 Student Riddle

Solve the riddle to win 5 points for your house. The first student to give the correct answer wins! A papal legate wants to attend a secret meeting being held by heretical Cathar knights. To be admitted, he must give a password to the guard at the door. He hides nearby and listens as the other people show up. A man arrives. The guard says to him, "five," the man replies, "four," and the guard allows him to pass. A second man turns up. The guard says to him, "six," to which he replies, "three," and is allowed in. A last man arrives. The guard says to him, "four," and he responds, "four," and enters. Now it's the papal legates turn. The guard says to him, "seven". What should he answer to gain entry?