Python 7 Levels, L3, Unit 29, Perpetual Calendar II

Exercise:

year_in = int(input("Please input year:"))
month_in = int(input("Please input month:"))
sum_day = 0
month_sumDay = 0
for year in range(1900,year_in):#days from Jan. 1, 1900 to Dec. 31, year_in -1
    if (year%4==0 and year%100!=0) or (year%400==0):
        sum_day += 366
    else:
        sum_day +=365
for month in range(1,month_in):##days from Jan. 1, year_in to the last day of month_in-1
    if month == 2:
        if (year_in%4==0 and year_in%100!=0) or (year_in%400==0):
            sum_day +=29
        else:
            sum_day+=28
    elif month == 4 or month == 6 or month ==9 or month == 11:
        sum_day += 30
    else:
        sum_day += 31
sum_day+=1#add month_in first day
week = sum_day%7
if month_in == 2:
    if (year_in % 4 == 0 and year_in % 100 != 0) or (year_in % 400 == 0):
        month_sumDay = 29
    else:
        month_sumDay = 28
elif month_in == 4 or month_in == 6 or month_in == 9 or month_in == 11 :
    month_sumDay = 30
else:
    month_sumDay = 31
print("\t\tYear: ",year_in,", Month:",month_in)
print("Sun.\tMon.\tTue.\tWed.\tThu.\tFri.\tSat.")
for i in range(0,week):
    print(end = "\t\t")
for day in range(1,month_sumDay+1):
    print(day,end = "\t\t")
    if sum_day%7 == 6:
        print()
    sum_day +=1