题解 | #自守数#

import java.util.*;

// 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 sc = new Scanner(System.in);
        int n = sc.nextInt();
        if(n<1 || n>10000) return;
        int count = 0;
        for(int i=0; i<=n; i++){
            String s1 = String.valueOf(i*i);
            int len1 = s1.length();
            String s2 = String.valueOf(i);
            int len2 = s2.length();
            if(s1.substring(len1-len2).equals(s2)){
                count++;
            }
        }
        System.out.println(count);
    }
}