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 n, ans;
void boost() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
}
int main() {
  boost();
  cin >> n;
  for (int a = 0; a <= 1; a++) {
    for (int b = 0; b <= 1; b++) {
      for (int c = 0; c <= 1; c++) {
        for (int d = 0; d <= 1; d++) {
          for (int e = 0; e <= 1; e++) {
            for (int first = 0; first <= 1; first++) {
              for (int g = 0; g <= 1; g++) {
                for (int h = 0; h <= 1; h++) {
                  for (int i = 0; i <= 1; i++) {
                    for (int j = 0; j <= 1; j++) {
                      if (a == 1 || b == 1 || c == 1 || d == 1 || e == 1 ||
                          first == 1 || g == 1 || h == 1 || i == 1 || j == 1) {
                        if (a * 1000000000 + b * 100000000 + c * 10000000 +
                                d * 1000000 + e * 100000 + first * 10000 +
                                g * 1000 + h * 100 + i * 10 + j <=
                            n) {
                          ans++;
                        }
                      }
                    }
                  }
                }
              }
            }
          }
        }
      }
    }
  }
  cout << ans;
}
