import sequtils,strutils

var
    N = stdin.readline.parseBiggestInt
    d = 3
    m = min(N, 2014 + 400 * 7)
    cnt : int64= 0
for i in 2015..m:
    if i mod 400 == 0:
        d = (2 + d) mod 7
    elif i mod 100 == 0:
        d = (1 + d) mod 7
    elif i mod 4 == 0:
        d = (2 + d) mod 7
    else:
        d = (1 + d) mod 7
    if d == 3:
        cnt += (N - i.int64) div (400 * 7) + 1
echo cnt