The Sun (United Kingdom):

Murdoch found he had such a rapport with Larry Lamb over lunch that other potential recruits as editor were not interviewed and Lamb was appointed as the first editor of the new Sun. He was scathing in his opinion of the Mirror, where he had recently been employed as a senior sub-editor, and shared Murdoch's view that a paper's quality was best measured by its sales, and he regarded the Mirror as overstaffed, and primarily aimed at an ageing readership. Lamb hastily recruited a staff of about 125 reporters, who were mostly selected for their availability rather than their ability.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". What did Lamb and Murdoch believe to be the best indicator of newspaper quality?
its sales