N = int(input())
P = 3
ans = 0
for i in range(2015,N+1):
    if i % 400 == 0:
        P += 2
    elif i % 100 == 0:
        P += 1
    elif i % 4 == 0:
        P += 2
    else:
        P += 1
    P %= 7
    if P == 3:
        ans += 1
print(ans)