题解 | #自守数#

import java.io.*;

public class Main {

public static void main(String[] args) throws IOException {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    String str = null;
    while ((str = br.readLine()) != null) {
        int n=Integer.valueOf(str);
        int count=0;
        for(int i=0;i<=n;i++){
           int temp=i;
            int j=1;
            while(temp!=0){
                temp=temp/10;
                j=j*10;
            }
            if((i*i-i)%j==0){
                count++;
            }
        }
        System.out.println(count);
    }
}

}