import java.util.*;
import java.lang.*;
import java.io.*;

// The main method must be in a class named "Main".
class Main {

    // Print Boundary
    public static void printBoundary(int [][] mat){
        int n = mat.length;

        //Top wall : row fixed = 0 
        for(int c=0 ; c<= n-2 ; c++){
            System.out.print(mat[0][c] + " ");
        }

        //Right wall : col fixed = n-1
        for(int r=0; r<=n-2; r++){
            System.out.print(mat[r][n-1] + " ");
        }

        //Bottom wall : Row fixed = n-1
        for(int c=n-1 ; c >=1 ; c--){
            System.out.print(mat[n-1][c] + " ");
        }

        //Left wall : Col fixed = 0 
        for(int r =n-1 ; r>=1 ; r--){
            System.out.print(mat[r][0] + " ");
        }
    }

    
    public static void main(String[] args) {
        int[][] mat = {
            {1, 2 , 3 , 4 },
            {5, 6 , 7 , 8 },
            {9, 10 , 11, 12 },
            {13 , 14 , 15 , 16 }
        };
        printBoundary(mat);
    }
}