Problem: Background: Belushi's mother, Agnes Demetri (Samaras), was the daughter of Albanian immigrants, and his father, Adam Anastos Belushi, was an Albanian immigrant from Qyteze. Born in Humboldt Park, a neighborhood on the West Side of Chicago, Illinois, John was raised in Wheaton, a suburb west of Chicago, along with his three siblings: younger brothers Billy and Jim, and sister Marian. Belushi was raised in the Albanian Orthodox Church and attended Wheaton Community High School, where he met his future wife, Judith Jacklin. In 1965, Belushi formed a band, the Ravens, together with four fellow high school students (Dick Blasucci, Michael Blasucci, Tony Pavolonis and Phil Special).
Context: In 1975 Chevy Chase and writer Michael O'Donoghue recommended Belushi to Lorne Michaels as a potential member for a television show Michaels was about to produce called Saturday Night a.k.a. Saturday Night Live (SNL). Michaels was initially undecided, as he was not sure if Belushi's physical humor would fit with what he was envisioning, but he changed his mind after giving Belushi an audition.  Over his four-year tenure at SNL, Belushi developed a series of successful characters, including the belligerent Samurai Futaba, Henry Kissinger, Ludwig van Beethoven, the Greek owner of the Olympia Cafe, Captain James T. Kirk, and a contributor of furious opinion pieces on Weekend Update, during which he coined his catchphrase, "But N-O-O-O-O-O-O-O-O-O!" With Aykroyd, Belushi created Jake and Elwood, the Blues Brothers. Originally intended to warm up the crowd before the show, the Blues Brothers were eventually featured as music guests. Belushi also reprised his Lemmings imitation of Joe Cocker. Cocker himself joined Belushi in 1976 to sing together Feeling Alright.  Like many of his SNL fellow cast members, Belushi began experimenting heavily with drugs to deal with the constant pressure. His unpredictable temper caused him to be fired (and immediately re-hired) by Michaels a number of times. In Rolling Stone's February 2015 appraisal of all 141 SNL cast members to that time, Belushi received the top ranking. "Belushi was the 'live' in Saturday Night Live," they wrote, "the one who made the show happen on the edge ... Nobody embodied the highs and lows of SNL like Belushi."
Question: What were his well known characters?
Answer: the belligerent Samurai Futaba, Henry Kissinger, Ludwig van Beethoven, the Greek owner of the Olympia Cafe, Captain James T. Kirk,

Problem: Background: David Michael Letterman (born April 12, 1947) is an American television host, comedian, writer, and producer. He hosted a late night television talk show for 33 years, beginning with the February 1, 1982, debut of Late Night with David Letterman on NBC, and ending with the May 20, 2015, broadcast of Late Show with David Letterman on CBS. In total, Letterman hosted 6,028 episodes of Late Night and Late Show, surpassing friend and mentor Johnny Carson as the longest-serving late night talk show host in American television history. In 1996 Letterman was ranked 45th on TV Guide's 50 Greatest TV Stars of All Time.
Context: In 1975, encouraged by his then-wife Michelle and several of his Sigma Chi fraternity brothers, Letterman moved to Los Angeles, with hope of becoming a comedy writer. He and Michelle packed their belongings in his pickup truck and headed west. As of 2012, he still owned the truck. In Los Angeles, he began performing comedy at The Comedy Store. Jimmie Walker saw him on stage; with an endorsement from George Miller, Letterman joined a group of comedians whom Walker hired to write jokes for his stand-up act, a group that at various times would also include Jay Leno, Paul Mooney, Robert Schimmel, Richard Jeni, Louie Anderson, Elayne Boosler, Byron Allen, Jack Handey, and Steve Oedekerk.  By the summer of 1977, Letterman was a writer and regular on the six-week summer series The Starland Vocal Band Show, broadcast on CBS. He hosted a 1977 pilot for a game show entitled The Riddlers (that was never picked up), and co-starred in the Barry Levinson-produced comedy special Peeping Times that aired in January 1978. Later that year, Letterman was a cast member on Mary Tyler Moore's variety show, Mary. Letterman made a guest appearance on Mork & Mindy (as a parody of EST leader Werner Erhard) and appearances on game shows such as The $20,000 Pyramid, The Gong Show, Hollywood Squares, Password Plus and Liar's Club, as well as the Canadian cooking show Celebrity Cooks (November 1977), talk shows such as 90 Minutes Live (February 24 and April 14, 1978), and The Mike Douglas Show (April 3, 1979 and February 7, 1980). He was also screen tested for the lead role in the 1980 film Airplane!, a role that eventually went to Robert Hays.  His dry, sarcastic humor caught the attention of scouts for The Tonight Show Starring Johnny Carson, and Letterman was soon a regular guest on the show. Letterman became a favorite of Carson and was a regular guest host for the show beginning in 1978. Letterman credits Carson as the person who influenced his career the most.
Question: Was he successful from the start?
Answer:
By the summer of 1977, Letterman was a writer and regular on the six-week summer series The Starland Vocal Band Show, broadcast on CBS.