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.
import sys
from sys import stdin

#your code goes here
def solve():
    n = int(input())
    dict = {}
    for i in range(1,2048):
        tmp = ""
        for j in range(0,12) :
            tmp += str(((i >> j) & 1))
        tmp = tmp[::-1]
        val = int(tmp)
        if val <= n :
            if val in dict :
                dict[val] += 1
            else :
                dict[val] = 1
    print(len(dict))

def main():
    #sys.stdin = open("test.inp", "r")
    solve()

if __name__ == "__main__":
    main()
