import datetime

n = int(input())
count = 0
for year in range(2015, n + 1):
    try:
        d = datetime.date(year, 12, 25)
        if d.weekday() == 3:  # Thursday is represented by 3
            count += 1
    except:
        pass  # This handles any invalid date, though December 25 is always valid
print(count)