/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
      int[] arr = {-1,2,-3,3};
      System.out.println(findMax(arr));
 	}
 
	static int findMax(int[] nums){
		int n = nums.length;
 
	    int max = Integer.MIN_VALUE;
    	 for(int i = 0;i<n;i++){
        for(int j=i;j<n;j++){
 
          if(i!= j && (nums[i] == -nums[j] ||  -nums[i] == nums[j])){
              max = Math.max(max,(Math.abs(nums[i])));
            }
        }
      }
      if(max == Integer.MIN_VALUE){
        return -1;
      }
 
      return max;   
    }
}

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