题解 | #自守数#

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);

        while (in.hasNextInt()) {
            int n = in.nextInt();
            int count = 0;

            for (int i = 0; i <= n; i++) {
                int square = (int) Math.pow(i, 2);
                String str = Integer.toString(square);
                String subStr = Integer.toString(i);
                int len = str.length();
                if (str.contains(subStr) &&
                        str.lastIndexOf(subStr) == len - subStr.length()) count = count + 1;
            }

            System.out.println(count);
        }
    }
}