N = int(input())

if N < 100:
    ans = N//3-3
else:
    S = str(N)
    c1 = 0
    c2 = 0
    f = True
    for i in range(len(S)):
        if i == 0:
            c1 = (int(S[i])-1)//3+1
        else:
            c1 = c1*4+c2*((int(S[i])+2)//3)
        if int(S[i])%3 == 0 and f:
            c2 = 1
        else:
            f = False
            c2 = 0
    ans = c1+c2+14
print(ans)