n = int(input())

def is_leap(y):
    if y % 4 != 0:
        return False
    if y % 100 != 0:
        return True
    return y % 400 == 0

current_day = 0  # 2014's December 21 is Sunday
count = 0

for year in range(2015, n + 1):
    if is_leap(year):
        delta = 2
    else:
        delta = 1
    current_day = (current_day + delta) % 7
    if current_day == 0:
        count += 1

print(count)