An AAU airline offers only flights in US and Mexico. Under special conditions a discount is offered $$ a discount with respect to the normal airfare.

Business Rules:

Passengers older than $18$ with destinations in US are offered a discount at $20\%,$ if the departure is not on a Tuesday or Saturday. If the passengers stay at least $10$ days at the destination, an additional discount of $10\%$ is offered. For destinations outside of US$,$ passengers are offered a discount of $25\%,$ if the departure is not on a Tuesday or Saturday. $$ Passengers older than $2$ but younger than $18$ years are offered a discount of $40\%$ for all destinations. Also, Children under $2$ travels for free.