One beautiful July morning a terrible thing happened in Mainframe: a mean virus Megabyte somehow got access to the memory of his not less mean sister Hexadecimal. He loaded there a huge amount of n different natural numbers from 1 to n to obtain total control over her energy.

But his plan failed. The reason for this was very simple: Hexadecimal didn't perceive any information, apart from numbers written in binary format. This means that if a number in a decimal representation contained characters apart from 0 and 1, it was not stored in the memory. Now Megabyte wants to know, how many numbers were loaded successfully.

Input

Input data contains the only number n (1 ≤ n ≤ 109).

Output

Output the only number — answer to the problem.

Examples

Input

10


Output

2

Note

For n = 10 the answer includes numbers 1 and 10.
n = int(input())
ans = 0
l = set([])
for i in range(2**10+1):
    t = '0'*10
    t = list(t)
    for j in range(0,10):
        if ((i&(2**j))>0):
            t[j]=1 
    t1 = t[:]
    t = ''
    for k in t1:
        t+=str(k)
    l.add(int(t))

for i in l:
    if (i<=n and i>0):
        
        ans+=1 
print(ans)