The 1940 Chicago Bears team holds the record for the biggest margin of victory in an NFL game (NFL playoffs or regular season) with a 73–0 victory over the Washington Redskins in the 1940 NFL Championship Game. The largest home victory for the Bears came in a 61–7 result against the Green Bay Packers in 1980. The largest defeat in club history was a 52–0 loss against the Baltimore Colts in 1964. The club recorded undefeated regular seasons in 1934 and 1942, but (unlike the 1972 Dolphins) did not win the championship game in either season. In 1934, the club completed a 13–0 record but were defeated by the New York Giants, and in 1942 the club completed an 11–0 record but were defeated by the Redskins. Had the Bears won either championship, the club would have completed a championship three-peat – a feat completed only by the Packers (twice), although no team has done it since the AFL-NFL merger. Halas holds the team record for coaching the most seasons with 40 and for having the most career victories of 324. Halas victories record stood until Don Shula surpassed Halas in . Ditka is the closest Bears coach to Halas, with 112 career victories. No other Bears coach has recorded over 100 victories with the team.
Question: How many teams completed a championship three-peat before the AFL-NFL merger?
Answer: 1