from datetime import datetime, date

N = int(input())

day = date(2014, 7, 23)
dow = day.weekday()

count = 0
for i in range(2015, N + 1):
    day_i = date(i, 7, 23)
    dow_i = day_i.weekday()
    if dow == dow_i:
        count += 1
        
print(count)