import java.util.Arrays;

import java.util.Comparator;

public class LineReflection {

public boolean isReflected(int[][] points) {

int min = Integer.MAX_VALUE;

int max = Integer.MIN_VALUE;

double line;

for(int[] point:points){

min = Math.min(min, point[0]);

max = Math.max(max, point[0]);

}

line = min+max;

Arrays.sort(points,new Comparator<int[]>() {

public int compare(int[] o1, int[] o2) {

if(o1[0] == o2[0]){

//on the left, ascending order

if(o1[0] < line/2){

return o1[1] - o2[1];

}

else{

// descending order

return o2[1] - o1[1];

}

}

return o1[0] - o2[0];

}

});

int l = points.length-1;

int i = 0;

while(i<=l){

while(i+1<=l && points[i][0] == points[i+1][0] && points[i][1] == points[i+1][1]){

i++;

}

while(i<=l && line %2== 0 && points[i][0] == line/2)

i++;

while(i<=l-1 && points[l][0] == points[l-1][0] && points[l][1] == points[l-1][1]){

l--;

}

while(i<=l && line%2 == 0 && points[l][0] == line/2)

l--;

if(i<=l && (points[i][0] + points[l][0] != line || points[i][1] != points[l][1]))

return false;

i++;

l--;

}

return true;

}

public static void main(String[] args) {

int[][] points = new int[][]{{1,2},{2,2},{1,4},{2,4}};

LineReflection lr = new LineReflection();

System.out.println(lr.isReflected(points));

}

}