The stock cannot be both gifted and inherited.
If you got it based on death, then it is inherited. It is then taxed as long term. You cost basis is the value at date of death.
If you got ownership prior to death it is a gift. your cost value is what the giver paid or Fair Market Value at time of the gift (whichever is lower).
This can be very significant difference, so please determine what it is a gift or inheritance.