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;
char a[20];
int compare(char *s, int n, int len) {
  char ch[20];
  int cnt = 0;
  while (n) {
    if (n % 2 == 0)
      ch[cnt++] = '0';
    else
      ch[cnt++] = '1';
    n /= 2;
  }
  if (cnt < len)
    return 1;
  else {
    for (int i = 0; i < len; i++) {
      if (a[i] > '1' || a[i] > ch[len - i - 1]) return 1;
      if (a[i] == '0' && ch[len - i - 1] == '1') return 0;
    }
    return 1;
  }
}
int main() {
  scanf("%s", a);
  char ch[20];
  int len = strlen(a), ans = 0;
  int ww = (1 << len) - 1;
  for (int i = 1; i <= ww; i++) {
    int flag = compare(a, i, len);
    if (flag) ans++;
  }
  printf("%d\n", ans);
  return 0;
}
