t1

def month(a):
    if (a > 12) or (a < 1) or (a%1 != 0):
        print("oh my god danila are you crazy")
    else:
        if (a < 8) and (a > 0) and (a%2 != 0):# а если double являктся ли это числом месяца?
            print("31")
        else:
            if (a == 8) or (a == 10) or (a == 12):
                print("31")
            else:
                if (a == 4) or (a == 6) or (a == 9) or (a == 11):
                    print("30")
                else:
                    if (a == 2):
                        print("29")
mon = int(input())
month(mon)