Java实现****************************************************

import java.util.Scanner;

public class Main {

public static void main(String[] args) {

// TODO Auto-generated method stub

Scanner scanner=new Scanner(System.in);

int n=scanner.nextInt();

int count=0;

for(int i=1;i<=n;i++)

{

int j=i;

while(j!=0)

{

if(j%10==1) count++;

j=j/10;

}

}

System.out.println(count);

}

}