N = int(input())
SN = str(N)
cnt = 0
if N < 100:
    print((N-9)//3)
    exit()
if int(SN[0]) < 3:
    N2 = [3] * (len(SN) - 1)
else:
    N2 = []
    while N > 0:
        N2.append((N%10)//3)
        N //= 10
ans = 30
tmp = 0
for i in reversed(N2):
    tmp *= 4
    tmp += i
ans += tmp - 15
print(ans)