from bisect import bisect_left, bisect_right
def cnt_ika(li, x): # x 以下の要素数
    return bisect_right(li, x)

N = int(input())

futaketa = [i for i in range(12, 100, 3)]

if N < 300:
    ans = cnt_ika(futaketa, N)
    exit(print(ans))

memo = []
flag = True
for s in str(N):
    if flag:
        if int(s)%3 == 0:
            memo.append(str(int(s)//3))
        else:
            flag = False
            memo.append(str(int(s)//3))
    else:
        # 3 を突っ込む
        memo.append('3')

# memo を4進数として見た時に何番目か？
number = int(''.join(memo), 4)
ans = 30 + (number - 15)
print(ans)