import datetime
import sys

sys.setrecursionlimit(10 ** 6)
int1 = lambda x: int(x) - 1
p2D = lambda x: print(*x, sep="\n")
def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]

def main():
    #2014年7月23日(水)
    n=int(input())
    ans=0
    for y in range(2015,n+1):
        d=datetime.date(y,7,23)
        ans+=d.weekday()==2
    print(ans)

main()