import java.util.Scanner;

class PrincipEleSum {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter the dimension of the square matrix: ");
        int n = sc.nextInt();
        int a[][] = new int[n][n];

        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                System.out.print(
                    "Enter the element at (" + i + "," + j + "): "
                );
                a[i][j] = sc.nextInt();
            }
        }

        System.out.print("The Principal Elements are: [ ");
        // Principal Element Printing and Sum
        int sum = 0;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                if (i == j) {
                    System.out.print(a[i][j] + " ");
                    sum += a[i][j];
                }
            }
        }
        System.out.println("]");
        System.out.println("Principal Element Sum: " + sum);
    }
}