from itertools import pairwise


def digits(x: int) -> list[int]:
    return [int(c) for c in str(x)]


def conv(x: int) -> int:
    base = 4

    def rec(x: int, b: int) -> int:
        if x == 0: return 0
        m = (x % base) * b * 3
        return m + rec(x//4, b*10)

    return rec(x, 1)


N = int(input())
ans = 0
for i in range(10, min(100, N+1)):  # 100以下は全探索
    if i % 3 != 0: continue
    if all((a+b) % 3 == 0 for a, b in pairwise(digits(i))):
        ans += 1

# 4進数で全探索
for i in range(1, N+1):
    x = conv(i)
    if x < 100: continue
    if x > N: break
    ans += 1

print(ans)