Write a function that takes time t1 and time t2 and returns the numbers of hours passed between the two times.
hoursPassed("3:00 AM", "9:00 AM") ➞ "6 hours"
hoursPassed("2:00 PM", "4:00 PM") ➞ "2 hours"
hoursPassed("1:00 AM", "3:00 PM") ➞ "14 hours"
t1 will always be the starting time and t2, the ending time."No time has passed." if t1 is equal to t2.