days = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]

day = 7  # first sunday in 1900
count = 0

for year in range(1900, 2001):
	for month in range(1, 13):
		if day == 1 and year >= 1901:
			count += 1
		if month == 2 and year % 4 == 0:
			day -= 1
		while(day <= days[month-1]):
			day += 7
		day -= days[month-1]

print count