import java.io.*; import java.util.*; /** * Read in the values. Scan over the array. Test each entry to see if it is * the corner of an L. For each distinct integer, there must be a grid entry * that is the corner of an L. Additionally, make sure that each positive * number is seen exactly 3 times. * * @author Finn Lidbetter */ public class ybtj2_finn { public static void main(String[] args) throws IOException { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); int n = Integer.parseInt(br.readLine()); int nVals = ((1<=0 && nr1=0 && nc1=0 && nr2=0 && nc2