StuckNums

import java.util.Arrays;
import java.util.Scanner;

public class _Problem01 {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int number = sc.nextInt();
        sc.nextLine();
        String[] input = sc.nextLine().split(" ");
        int stuckCount = 0;

        for (int i = 0; i < input.length; i++) {
            for (int j = 0; j < input.length; j++) {
                if (j == i) {
                    continue;
                }else {
                    for (int j2 = 0; j2 < input.length; j2++) {
                        for (int k = 0; k < input.length; k++) {
                            if (j2 != i && j2 != j && k != i && k!= j && k != j2) {
                                if ((input[i] + input[j]).equals(input[j2] + input[k])) {
                                    System.out.printf("%1$s|%2$s==%3$s|%4$s", input[i], input[j],
                                            input[j2], input[k]);
                                    System.out.println();
                                    stuckCount++;
                                }
                            }

                        }
                    }
                }

            }
        }
        if (stuckCount == 0) {
            System.out.println("No");
        }

    }
}