Prompt the user two STRING inputs of time instances in the format of: YYYY/MM/DD HH:NN:SS. Use string manipulations to figure out the units (year, minute, etc.). The output is the total elapsed time in seconds between the two time inputs.
Inputs: Time 1 in YYYY/MM/DD HH:NN:SS
Time 2 in YYYY/MM/DD HH:NN:SS
Time 2 >= Time 1
Output: (Time 2 - Time 1) in seconds
check valid and invalid