Why it is not submitting the code is perfectly fine and running??(Java for beginners)

import java.util.*;

import java.util.InputMismatchException;

public class Main {

public static void main(String[] args) {

int i, j, stu, sub;

Scanner sc = new Scanner(System.in);

stu = sc.nextInt();

sub = sc.nextInt();

String[] name = new String[stu];

double[][] num = new double[stu][sub];

for (i = 0; i < stu; i++) {

name[i] = sc.next();

for (j = 0; j < sub; j++) {

num[i][j] = sc.nextDouble();

}

}

System.out.println("Average Grades:");

for (i = 0; i < stu; i++) {

double sum = 0;

for (j = 0; j < sub; j++) {

sum += num[i][j];

}

System.out.println(name[i] + ":" + (sum / sub));

}

double max=Double.MIN_VALUE;

double min=Double.MAX_VALUE;

String maxGread = null;

String minGread = null;

for(i=0;i<stu;i++)

{

for(j=0;j<sub;j++)

{

if(num[i][j]>max)

{

max=num[i][j];

maxGread=name[i];

}

if(num[i][j]<min)

{

min=num[i][j];

minGread=name[i];

}

}

}

System.out.println("Higest Grade:"+max+"("+maxGread+")");

System.out.println("Lowest Grade:"+min+"("+minGread+")");

}

}