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

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

        System.out.print("Введите количество элементов: ");
        int n = scanner.nextInt();

        int[] numbers = new int[n];

        for (int i = 0; i < numbers.length; i++) {
            numbers[i] = scanner.nextInt();
        }

        for (int i = 0; i < numbers.length - 1; i += 2) {
            int temp = numbers[i];
            numbers[i] = numbers[i + 1];
            numbers[i + 1] = temp;
        }

        System.out.println(Arrays.toString(numbers));
    }
}