純粹邏輯思考，不必利用prob的公式
P(First card is a heart or at least one card is a heart)
=P(at least one card is a heart)
= 1- P(no cards are hearts)
= 1- (52-13)/52 x (51-13)/51
P(First card is a heart and at least one card is a heart)
=P(First card is a heart)
= 13/52 x 51/51
