import numpy as np

def cond1(x):
    return len(str(x)) >= 2 and x % 3 == 0

def cond2(x):
    x = str(x)
    D = len(x)
    for i in range(D):
        for j in range(i + 1, D):
            p = int(x[i]) + int(x[j])
            if p % 3 != 0:
                return False
    return True

def cond3(x):
    x = str(x)
    D = len(x)
    for i in x:
        if int(i) % 3 == 0:
            return False
    return True

def cond(x):
    return cond1(x) and cond2(x)

n = int(input()) + 1    # 未満

if n <= 1000:
    res = 0
    for i in range(n):
        res += cond(i)
    print(res)
    exit(0)

s = str(n)
d = len(s)

res = 0
for j in range(min(100, n)):
    if cond(j) and cond3(j):
        res += 1

dp = np.zeros((d + 1, 2), dtype='i')
dp[0, 0] = 1

for i in range(d):
    dig = int(s[i])
    # dp[.][0] : 小さいことが未確定
    for j in range(0, 10, 3):
        if j > dig:
            break
        if j == dig:
            dp[i + 1][0] += dp[i][0]
        else:
            dp[i + 1][1] += dp[i][0]
    # dp[.][1] : 小さいことが確定
    for j in range(0, 10, 3):
        dp[i + 1][1] += dp[i][1]

print(dp[d, 1] + res - 4)