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);
        // 注意 hasNext 和 hasNextLine 的区别
        int a = in.nextInt();
        int count = 2;
        int sum = 0;
        if (a == 0) {
            System.out.print(1);
        } else if (a < 5) {
            System.out.print(2);
        } else {
            for (int i = 5; i <= a; i++) {
                sum = i * i;
                String d = String.valueOf(sum);
                if (d.endsWith(String.valueOf(i))) {
                    count++;
                }
            }
            System.out.print(count);
        }
    }
}