#include<stdio.h>

int main()
{	
	int n = 0;
	scanf("%d", &n);

	int Image[25][25]={};
	for( int i=0; i<n; i+=1 )
	{
		for( int j=0; j<n; j+=1 )
		{
			scanf("%d",&Image[i][j]);
		}
	}

	int Max_Pooling[25][25]={};
	for( int i=0; i<n; i+=2 )
	{
		for( int j=0; j<n; j+=2 )
		{
			int Max = 0;
			
			if( Image[i][j] > Max )
				Max = Image[i][j];
			if( Image[i][j+1] > Max )
				Max = Image[i][j+1];
			if( Image[i+1][j] > Max )
				Max = Image[i+1][j];
			if( Image[i+1][j+1] > Max )
				Max = Image[i+1][j+1];

			Max_Pooling[i/2][j/2] = Max;
		}	
	}

	for( int i=0; i<n/2; i+=1 )
	{
		for( int j=0; j<n/2; j+=1 )
		{
			printf("%d ", Max_Pooling[i][j]);
		}
		printf("\n");
	}

	return 0;
}