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 scanner = new Scanner(System.in); scanner.useDelimiter("\n"); while (scanner.hasNextInt()) { int i = scanner.nextInt(); int res = 0; for (int j = 0; j <= i; j++) { String ping = j * j + ""; String original = j + ""; if (ping.endsWith(original)) { res++; } } System.out.println(res); } } }