Dare I say "welcome back, Nilton?"
I would take exception to the "rule" that you cannot begin a sentence with the word "But." I think this is a "grammar myth."
Shakespeare did it: "But how is it that great Plantagenet/Is crown'd so soon, and broke his solemn oath?"
Mark Twain did it: "A glance at the long lines of heads was apt to make one think it was all gray. But it was not."--The Innocents Abroad
James Joyce did it: "He had given two and still Wells laughed. But Wells must know the right answer for he was in third of grammar."--Portrait of the Artist as a Young Man
Charles Dickens did it: "But, like many fond parents, I have in my heart of hearts a favourite child. And his name is David Copperfield." Not only does he start a sentence with "but," he starts the next one with "and!" Oh, the horror!
The translator of "Dom Casmurro," by Machado de Assis, in _The Library of Latin America_ series, did it: "The journey was short, and it may be that the verses were not entirely bad. But it so happened that I was tired, and closed my eyes three or
four times..."