import math

n = int(input())
d = int(math.log10(n)) + 1
digits = [int(c) for c in str(n)]

leading_zero = [0, 0, 30] + [3*4**i for i in range(2, 10)]
if n < 100:
    cnt = 0
    for i in range(12, n+1, 3):
        cnt += 1
    print(cnt)
else:
    dp = [[0]*2 for i in range(d+1)]
    GREATEST = 0
    LESS = 1
    dp[0][GREATEST] = 1 if digits[0] % 3 == 0 else 0
    dp[0][LESS] = ((digits[0]-1)//3)
    for i in range(0, d):
        dp[i+1][GREATEST] = dp[i][GREATEST] * (1 if digits[i] % 3 == 0 else 0)
        dp[i+1][LESS] = dp[i][GREATEST] * ((digits[i]-1)//3 + 1)
        dp[i+1][LESS] = dp[i][LESS] * (digits[i]//3 + 1)
    print(sum(dp[d]) + sum(leading_zero[:d]))