import java.util.Scanner;
 
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        if (!sc.hasNextLine()) return;
        String s = sc.nextLine();
 
        boolean L1 = false;
        boolean f = false;
 
        String[] words = s.trim().split("\\s+");
 
        for (String w : words) {
            if (w.length() >= 2) {
                char[] c = w.toCharArray();
                if (c[0] == c[1]) {
                    System.out.println(w);
                    f = true;
                }
            }
        }
 
        if (!f) {
            L1 = true;
            System.out.println("L1 = " + L1);
        }
    }
}
 

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

0L3QtdC30YDRltCy0L3Rj9C90L3QsCDRgtGD0LzQsNC90L3QsCDRgtC40YjQsCDQvtCz0L7RgNC90YPQu9CwINGB0L7QvdC90YMg0LTQvtC70LjQvdGD

незрівнянна туманна тиша огорнула сонну долину