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.
#include <bits/stdc++.h>
using namespace std;
int a[11], ans, n;
int main() {
  cin >> n;
  for (a[1] = 0; a[1] <= 1; a[1] += 1)
    for (a[2] = 0; a[2] <= 10; a[2] += 10)
      for (a[3] = 0; a[3] <= 100; a[3] += 100)
        for (a[4] = 0; a[4] <= 1000; a[4] += 1000)
          for (a[5] = 0; a[5] <= 10000; a[5] += 10000)
            for (a[6] = 0; a[6] <= 100000; a[6] += 100000)
              for (a[7] = 0; a[7] <= 1000000; a[7] += 1000000)
                for (a[8] = 0; a[8] <= 10000000; a[8] += 10000000)
                  for (a[9] = 0; a[9] <= 100000000; a[9] += 100000000)
                    for (a[10] = 0; a[10] <= 1000000000; a[10] += 1000000000) {
                      int s = 0;
                      for (int i = 1; i <= 10; i++) s += a[i];
                      if (s != 0 && s <= n) ans++;
                    }
  cout << ans;
  return 0;
}
