n = int(input())

if len(str(n)) <= 2:
    print(n // 3 - 3)
    exit()

ans = 30 - 15
tmp = ""
cnt = 0
for i in str(n):
    if int(i) % 3 != 0:
        tmp += str(int(i) + (3 - int(i) % 3))
    else:
        cnt += 1
        tmp += i

for i, j in enumerate(tmp[::-1]):
    ans += int(j) // 3 * (4 ** i)
if cnt == len(str(n)):
    print(ans)
else:
    print(ans - 1)