Given the following context:

In the interim came The Beatles, a double LP commonly known as the White Album for its virtually featureless cover. Creative inspiration for the album came from a new direction: without Epstein's guiding presence, the group had briefly turned to Maharishi Mahesh Yogi as their guru. At his ashram in Rishikesh, India, a "Guide Course" scheduled for three months marked one of their most prolific periods, yielding numerous songs including a majority of the 30 included on the album. However, Starr left after only ten days, likening it to Butlins, and McCartney eventually grew bored and departed a month later. For Lennon and Harrison, creativity turned to questioning when an electronics technician known as Magic Alex suggested that the Maharishi was attempting to manipulate them. When he alleged that the Maharishi had made sexual advances to women attendees, a persuaded Lennon left abruptly just two months into the course, bringing an unconvinced Harrison and the remainder of the group's entourage with him. In anger, Lennon wrote a scathing song titled "Maharishi", renamed "Sexy Sadie" to avoid potential legal issues. McCartney said, "We made a mistake. We thought there was more to him than there was."During recording sessions for the White Album, which stretched from late May to mid-October 1968, relations between the Beatles grew openly divisive. Starr quit for two weeks, and McCartney took over the drum kit for "Back in the U.S.S.R." (on which Harrison and Lennon drummed as well) and "Dear Prudence". Lennon had lost interest in collaborating with McCartney, whose contribution "Ob-La-Di, Ob-La-Da" he scorned as "granny music shit". Tensions were further aggravated by Lennon's romantic preoccupation with avant-garde artist Yoko Ono, whom he insisted on bringing to the sessions despite the group's well-established understanding that girlfriends were not allowed in the studio. Describing the double album, Lennon later said: "Every track is an individual track; there isn't any Beatle music on it. [It's] John and the...

answer the following question:

What was the name of the person who grew bored of the Guide Course? 

McCartney