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>
int main() {
  int n, m;
  long long b(1);
  std::vector<long long> v = {{0, 1}};
  std::scanf("%d", &n);
  for (int i(0); i < 10; ++i) {
    b *= 10;
    m = v.size();
    for (int j(0); j < m; ++j) {
      v.push_back(b + v[j]);
    }
  }
  m = (int)(std::upper_bound(v.begin(), v.end(), (long long)n) - v.begin()) - 1;
  std::printf("%d\n", m);
  return 0;
}
