Funny discussion about the numbers of the mating combination. Is it 3, 4 or 5? IMO it is in this particular situation mate in 4, not in 5 and certainly not mate in 3.
It is not a mate in 3, because you will have to take the sacrifice of the knight into account. It clears a field for the black king by which he might escape. The sacrifice of the knight outweighs the sacrifice of the white queen. Hence, you will have to calculate this move to be sure of the combination.
It is not a mate in 5 imo because that is the computorized answer to the question: how many moves can black legally make before he is mated? Off course would it be a mate in 5 if it was created as a puzzle, but this is a position in a game. In the game both players know that the counterattack starting with the queen has no impact. They would not consider that move in this combination. Qf2:+ is an obsolete move.
If it was a puzzle, mate in 5, coming from a game, mate in 4.
By the way, I tried to find a mate in 3, but I could only find a mate in 4 and did not see the counterattack of the queen. At my first analysis of the position I saw that the defense of white was very good, never leading to a successful counterattack of black. The second puzzle was very easy, because the rook was undefended.
hahahahahaha it is mate in 3,33333333333333333333333333333333333333333333333333333333333333333333333333