_01_MirrorNumbers

import java.util.Scanner;

public class _01_MirrorNumbers {

    public static void main(String[] args) {
        @SuppressWarnings("resource")
        Scanner input = new Scanner(System.in);
        int num = Integer.parseInt(input.nextLine());
        String nums = input.nextLine();
        String[] numsStrings = nums.split(" ");
        boolean exist = false;
        for (int i1 = 0; i1 < num; i1++) {
            for (int i2 = i1 + 1; i2 < num; i2++) {
                if (!numsStrings[i1].equals(numsStrings[i2])) {
                    String reverse = new StringBuffer(numsStrings[i2]).reverse().toString();
                    if ( numsStrings[i1].equals(reverse)) {
                        System.out.printf("%s<!>%s\n", reverse, numsStrings[i2]);
                        exist = true;
                    }
                }
            }
        }
        if (!exist) {
            System.out.println("No");
        }
    }
}