题解 | #自守数#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int number = in.nextInt();
        int result = 0;
        for (int i = 0; i <= number; i++) {
            int pow = i * i;
            String powStr = String.valueOf(pow);
            String iStr = String.valueOf(i);
            String substring = powStr.substring(powStr.length() - iStr.length());
            if(iStr.equals(substring)) {
                result++;
            }
        }
        System.out.println(result);
    }
}