I keep getting runtime error for my java code. Please help.
import java.util.*;
import java.io.*;
public class main {
public static void main(String[] args) throws java.lang.Exception {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
StringBuilder builder = new StringBuilder();
int numCases = Integer.parseInt(reader.readLine().split(" ")[0]);
reader.readLine();
for (int i = 1; i <= numCases; i++){
builder.append("Case " + i + ": ");
int numPoints = Integer.parseInt(reader.readLine().split(" ")[0]);
reader.readLine();
float big = 0;
int add = 0;
for (int x = 1; x <= numPoints; x++){
String temp = reader.readLine();
reader.readLine();
float a = Float.parseFloat(temp.split(" ")[0]);
float b = Float.parseFloat(temp.split(" ")[1]);
if (a*a + b*b > big){
big = a*a + b*b;
add = x;
}
}
builder.append(add);
builder.append(System.getProperty("line.separator"));
builder.append(System.getProperty("line.separator"));
}
System.out.print(builder.toString());
//get numcases
//for numcases, add case # to builder, get numpoints
//for numpoints find largest squares, add largest squares in builder
}
}