What are the 4 mitzvot of Purim?

There are 4 mitzvot that are performed on Purim:

1. Reading of the Megillat Esther (the book of Esther)
2. Matanot L'Evyonim or Gifts to the poor - One must give charity gifts to at least two people.
3. Mishloach Manot or sending of food portions - One must send at least one package containing two types of foods to someone.
4. Seudah or Festive Purim meal - One must partake in a festive meal on Purim day