A standard deck of playing cards has 52 cards divided into four suits (clubs, diamonds, hearts, spades). Each suit consists of nine "number cards," each containing a different number from 2 to 10, and four "face cards" that include a jack, a queen, a king, and an ace. In the game of Cribbage, points are earned if you can combine two cards that sum to 15. Jacks, queens and kings each have a value of 10, aces each have a value of 1, and all number cards have a value of the number shown. How many different unordered pairs of two cards sum to 15 in a standard 52-card deck?