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 data contains the only number *n* (1 ≤ *n* ≤ 10<sup class="upper-index">9</sup>).
For *n* = 10 the answer includes numbers 1 and 10.
10
2
20
3
72
3
99
3
100
4
101
5
102
5
111
7
112
7
745
7
23536
31
1
1
1010011
83
312410141
511
1000000000
512
999999999
511
111111111
511
101010101
341
121212121
511
106341103
383
901556123
511
832513432
511
3
1
732875234
511
7
1
9
1
2
1
11
3
12
3
13
3
101020101
351
111100100
484
110110101
437
100111001
313
100100
36
110100102
421
def func(a):
    if(len(a)==0):
        return 0
    if(a[0]=="0"):
        return func(a[1:])
    if(len(a.replace('0',''))==0):
        return 0
    #print(a)

    b = int(a)
    sum = 0;
    sum+=2**(len(a)-1)-1
    minc=int(a[0])
    c1 = 0
    for i in range(len(a)):
        if(minc>int(a[i])):
            minc=int(a[i])
        if(a[i]>'1' and minc>0):
            sum+=2**(len(a)-1)
            return sum
        if(a[i]=='0'):
            sum+=max(0, (2**(i-1)-1)*2**(len(a)-i))
            #print("max",(2**(i-1)-1),(2**(i-2)-1)*2**(len(a)-i))
            sum+=func(a[i+1:])+1
            #print("sum",sum)
            return sum

    sum+=2**(len(a)-1)
    return sum
a = input()
b = int(a)
print(func(a))
#sum2=0;
#for i in range(1,b+1):
#    if(len(str(i).replace('0','').replace('1',''))==0):
#        sum2+=1
#print(sum2)
