题解 | #自守数#

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while (in.hasNextInt()) { 
            int cnt = 0;
            int a = in.nextInt();
            for(int i = 0; i<=a; i++){
                double p = Math.pow(i,2);
                String s = (int)p+"";
                String s1 = i+"";
                if(s1.equals(s.substring(s.length()-s1.length(),s.length()))){
                    cnt++;
                }
            }
            System.out.print(cnt);
        }
    }
}