from bisect import bisect_right
import itertools

n = int(input())
ans = [i * 3 for i in range(4, 34)]
for lst in itertools.product("0369", repeat = 9):
    num = int("".join(lst))
    if num // 100 == 0:
        continue
    ans.append(num)
ans.sort()
print(bisect_right(ans, n))