from datetime import *
from decimal import Decimal

N = Decimal(input().strip())

st = datetime.now()
count = 0
i = 12
while i <= N:
    if i < 100:
        count += 1
    else:
        if str(i)[0:1] == '1':
            i = 3 * (10 ** (len(str(i)) - 1))
            continue
        elif str(i)[0:1] == '4':
            i = 6 * (10 ** (len(str(i)) - 1))
            continue
        elif str(i)[0:1] == '7':
            i = 9 * (10 ** (len(str(i)) - 1))
            continue

        if '1' in str(i):
            pass
        elif '2' in str(i):
            pass
        elif '4' in str(i):
            pass
        elif '5' in str(i):
            pass
        elif '7' in str(i):
            pass
        elif '8' in str(i):
            pass
        else:
            count += 1
    i += 3

print(count)

print(datetime.now() - st)