Daynum = 1
monthpos = 1
daypos = 2
year = 1901
count = 0
while year < 2001:
        while monthpos < 13:
            if daypos%7 == 0:
                count = count + 1
            if monthpos == 1 or monthpos == 3 or monthpos == 5 or monthpos ==7 or monthpos==8 or monthpos==10 or monthpos==12:
                daypos = daypos + 3
                monthpos = monthpos + 1
            elif monthpos == 4 or monthpos==6 or monthpos==9 or monthpos==11:
                daypos = daypos + 2
                monthpos = monthpos + 1
            else:
                if year%4 > 0:
                    daypos = daypos
                    monthpos = monthpos + 1
                else:
                    daypos = daypos + 1
                    monthpos = monthpos + 1
        monthpos = 1
        year = year + 1
print(count)