Get next day of a given dateΒΆ

Get next day of a given date.
Expected output:
Input a year: 2016
Input a month [1-12]: 08
Input a day [1-31]: 23
The next date is [yyyy-mm-dd] 2016-8-24
year = int(input("Input a year: "))

if (year % 400 == 0):
    leap_year = True
elif (year % 100 == 0):
    leap_year = False
elif (year % 4 == 0):
    leap_year = True
else:
    leap_year = False

month = int(input("Input a month [1-12]: "))

if month in (1, 3, 5, 7, 8, 10, 12):
    month_length = 31
elif month == 2:
    if leap_year:
        month_length = 29
    else:
        month_length = 28
else:
    month_length = 30

day = int(input("Input a day [1-31]: "))

if day < month_length:
    day += 1
else:
    day = 1
    if month == 12:
        month = 1
        year += 1
    else:
        month += 1

print("The next date is [yyyy-mm-dd] %d-%d-%d." % (year, month, day))

Output:

Input a year: 1974
Input a month [1-12]: 2
Input a day [1-31]: 15
The next date is [yyyy-mm-dd] 1974-2-16.