n=int(input())
sn=str(n)
ln=["0","3","6","9"]
ans=30
if len(sn)<3:
    ans=n//3-3
else:
    for i in range(3,len(sn)):
        ans+=3*(4**(i-1))
    for i in range(1,4):
        if int(sn[0])<int(ln[i]):
            break
        for j in range(4**(len(sn)-1)):
            num=ln[i]
            num2=j
            for k in range(len(sn)-1):
                num+=ln[num2%4]
                num2//=4
            if int(num)<=n:
                ans+=1
print(ans)