Liar, liar, pants on fire.
Knave of Hearts: I am telling the truth
Knave of Clubs: The Knave of Hearts is lying
Knave of Diamonds: The Knave of Clubs is lying
Knave of Spades: The Knave of Clubs is lying
If we know for sure that at least 2 Knaves are telling the truth, how many Knaves can we assume are telling the truth?