Case8. Two integers are given: D (day) and M (month), which determine the correct date of a non-leap year. Output the values of D and M for the date preceding the specified date.

Solution in Python 3:

import random

M = random.randrange(1,13)
#M=1
month = {
    1: 31,
    2: 28,
    3: 31,
    4: 30,
    5: 31,
    6: 30,
    7: 31,
    8: 31,
    9: 30,
    10: 31,
    11: 30,
    12: 31
}
try:
    D_Max = month[M]
    D = random.randrange(1,D_Max+1)
    #D = 1
    print("Date:")
    print("Month: {0}. Day: {1}".format(M,D))
    if D > 1:
        D -= 1
    else:
        if M == 1:
            M = 12
        else:
            M -=1
        D = month[M]
    print("Preceding date:")
    print("Month: {0}. Day: {1}".format(M,D))
except KeyError as e:
    print('Error')