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.
import java.util.Arrays;
import java.util.Scanner;
public class Hexli {
    public static void main(String[] args){
        Scanner key=new Scanner(System.in);
        int arr[]={1,
                10,
                11,
                100,
                101,
                110,
                111,
                1000,
                1001,
                1010,
                1011,
                1100,
                1101,
                1110,
                1111,
                10000,
                10001,
                10010,
                10011,
                10100,
                10101,
                10110,
                10111,
                11000,
                11001,
                11010,
                11011,
                11100,
                11101,
                11110,
                11111,
                100000,
                100001,
                100010,
                100011,
                100100,
                100101,
                100110,
                100111,
                101000,
                101001,
                101010,
                101011,
                101100,
                101101,
                101110,
                101111,
                110000,
                110001,
                110010,
                110011,
                110100,
                110101,
                110110,
                110111,
                111000,
                111001,
                111010,
                111011,
                111100,
                111101,
                111110,
                111111,
                1000000,
                1000001,
                1000010,
                1000011,
                1000100,
                1000101,
                1000110,
                1000111,
                1001000,
                1001001,
                1001010,
                1001011,
                1001100,
                1001101,
                1001110,
                1001111,
                1010000,
                1010001,
                1010010,
                1010011,
                1010100,
                1010101,
                1010110,
                1010111,
                1011000,
                1011001,
                1011010,
                1011011,
                1011100,
                1011101,
                1011110,
                1011111,
                1100000,
                1100001,
                1100010,
                1100011,
                1100100,
                1100101,
                1100110,
                1100111,
                1101000,
                1101001,
                1101010,
                1101011,
                1101100,
                1101101,
                1101110,
                1101111,
                1110000,
                1110001,
                1110010,
                1110011,
                1110100,
                1110101,
                1110110,
                1110111,
                1111000,
                1111001,
                1111010,
                1111011,
                1111100,
                1111101,
                1111110,
                1111111,
                10000000,
                10000001,
                10000010,
                10000011,
                10000100,
                10000101,
                10000110,
                10000111,
                10001000,
                10001001,
                10001010,
                10001011,
                10001100,
                10001101,
                10001110,
                10001111,
                10010000,
                10010001,
                10010010,
                10010011,
                10010100,
                10010101,
                10010110,
                10010111,
                10011000,
                10011001,
                10011010,
                10011011,
                10011100,
                10011101,
                10011110,
                10011111,
                10100000,
                10100001,
                10100010,
                10100011,
                10100100,
                10100101,
                10100110,
                10100111,
                10101000,
                10101001,
                10101010,
                10101011,
                10101100,
                10101101,
                10101110,
                10101111,
                10110000,
                10110001,
                10110010,
                10110011,
                10110100,
                10110101,
                10110110,
                10110111,
                10111000,
                10111001,
                10111010,
                10111011,
                10111100,
                10111101,
                10111110,
                10111111,
                11000000,
                11000001,
                11000010,
                11000011,
                11000100,
                11000101,
                11000110,
                11000111,
                11001000,
                11001001,
                11001010,
                11001011,
                11001100,
                11001101,
                11001110,
                11001111,
                11010000,
                11010001,
                11010010,
                11010011,
                11010100,
                11010101,
                11010110,
                11010111,
                11011000,
                11011001,
                11011010,
                11011011,
                11011100,
                11011101,
                11011110,
                11011111,
                11100000,
                11100001,
                11100010,
                11100011,
                11100100,
                11100101,
                11100110,
                11100111,
                11101000,
                11101001,
                11101010,
                11101011,
                11101100,
                11101101,
                11101110,
                11101111,
                11110000,
                11110001,
                11110010,
                11110011,
                11110100,
                11110101,
                11110110,
                11110111,
                11111000,
                11111001,
                11111010,
                11111011,
                11111100,
                11111101,
                11111110,
                11111111,
                100000000,
                100000001,
                100000010,
                100000011,
                100000100,
                100000101,
                100000110,
                100000111,
                100001000,
                100001001,
                100001010,
                100001011,
                100001100,
                100001101,
                100001110,
                100001111,
                100010000,
                100010001,
                100010010,
                100010011,
                100010100,
                100010101,
                100010110,
                100010111,
                100011000,
                100011001,
                100011010,
                100011011,
                100011100,
                100011101,
                100011110,
                100011111,
                100100000,
                100100001,
                100100010,
                100100011,
                100100100,
                100100101,
                100100110,
                100100111,
                100101000,
                100101001,
                100101010,
                100101011,
                100101100,
                100101101,
                100101110,
                100101111,
                100110000,
                100110001,
                100110010,
                100110011,
                100110100,
                100110101,
                100110110,
                100110111,
                100111000,
                100111001,
                100111010,
                100111011,
                100111100,
                100111101,
                100111110,
                100111111,
                101000000,
                101000001,
                101000010,
                101000011,
                101000100,
                101000101,
                101000110,
                101000111,
                101001000,
                101001001,
                101001010,
                101001011,
                101001100,
                101001101,
                101001110,
                101001111,
                101010000,
                101010001,
                101010010,
                101010011,
                101010100,
                101010101,
                101010110,
                101010111,
                101011000,
                101011001,
                101011010,
                101011011,
                101011100,
                101011101,
                101011110,
                101011111,
                101100000,
                101100001,
                101100010,
                101100011,
                101100100,
                101100101,
                101100110,
                101100111,
                101101000,
                101101001,
                101101010,
                101101011,
                101101100,
                101101101,
                101101110,
                101101111,
                101110000,
                101110001,
                101110010,
                101110011,
                101110100,
                101110101,
                101110110,
                101110111,
                101111000,
                101111001,
                101111010,
                101111011,
                101111100,
                101111101,
                101111110,
                101111111,
                110000000,
                110000001,
                110000010,
                110000011,
                110000100,
                110000101,
                110000110,
                110000111,
                110001000,
                110001001,
                110001010,
                110001011,
                110001100,
                110001101,
                110001110,
                110001111,
                110010000,
                110010001,
                110010010,
                110010011,
                110010100,
                110010101,
                110010110,
                110010111,
                110011000,
                110011001,
                110011010,
                110011011,
                110011100,
                110011101,
                110011110,
                110011111,
                110100000,
                110100001,
                110100010,
                110100011,
                110100100,
                110100101,
                110100110,
                110100111,
                110101000,
                110101001,
                110101010,
                110101011,
                110101100,
                110101101,
                110101110,
                110101111,
                110110000,
                110110001,
                110110010,
                110110011,
                110110100,
                110110101,
                110110110,
                110110111,
                110111000,
                110111001,
                110111010,
                110111011,
                110111100,
                110111101,
                110111110,
                110111111,
                111000000,
                111000001,
                111000010,
                111000011,
                111000100,
                111000101,
                111000110,
                111000111,
                111001000,
                111001001,
                111001010,
                111001011,
                111001100,
                111001101,
                111001110,
                111001111,
                111010000,
                111010001,
                111010010,
                111010011,
                111010100,
                111010101,
                111010110,
                111010111,
                111011000,
                111011001,
                111011010,
                111011011,
                111011100,
                111011101,
                111011110,
                111011111,
                111100000,
                111100001,
                111100010,
                111100011,
                111100100,
                111100101,
                111100110,
                111100111,
                111101000,
                111101001,
                111101010,
                111101011,
                111101100,
                111101101,
                111101110,
                111101111,
                111110000,
                111110001,
                111110010,
                111110011,
                111110100,
                111110101,
                111110110,
                111110111,
                111111000,
                111111001,
                111111010,
                111111011,
                111111100,
                111111101,
                111111110,
                111111111,
                1000000000};
       int n=key.nextInt();
        int len=arr.length;
        int k=Arrays.binarySearch(arr,n);
        if(k>=0){
            System.out.println(k+1);
        }
        else{
            System.out.println(-k-1);
        }
        System.exit(0);
    }
}