Phone Prices

Chef wants to buy a new phone, but he is not willing to spend a lot of money. Instead, he checks the price of his chosen model everyday and waits for the price to drop to an acceptable value. So far, he has observed the price for $N$ days (numbere $1$ through $N$); for each valid $i$, the price on the $i$-th day was $P_i$ dollars. On each day, Chef considers the price of the phone to be *good*