In May 1944, as the war began to turn in favor of the Allies, WCBW reopened the studios and the newscasts returned, briefly anchored by Ned Calmer, and then by Everett Holles. After the war, expanded news programs appeared on the WCBW schedule - whose call letters were changed to WCBS-TV in 1946 - first anchored by Milo Boulton, and later by Douglas Edwards. On May 3, 1948, Edwards began anchoring CBS Television News, a regular 15-minute nightly newscast on the CBS television network, including WCBS-TV. It aired every weeknight at 7:30 p.m., and was the first regularly scheduled, network television news program featuring an anchor . NBC's offering at the time, NBC Television Newsreel , was simply film footage with voice narration. In 1950, the name of the nightly newscast was changed to Douglas Edwards with the News, and the following year, it became the first news program to be broadcast on both coasts, thanks to a new coaxial cable connection, prompting Edwards to use the greeting "Good evening everyone, coast to coast." The broadcast was renamed the CBS Evening News when Walter Cronkite replaced Edwards in 1962. Edwards remained with CBS News with various daytime television newscasts and radio news broadcasts until his retirement on April 1, 1988.
Question: How many years after Edwards began anchoring CBS Television News did he retire from CBS?
Answer: 40