Untitled

import java.io.*;
import java.util.*;


 // } Driver Code Ends
//User function Template for Java


class Solution
{
    long findSwapValues(long A[], int n, long  B[], int m)
    {
        Arrays.sort(A);
        Arrays.sort(B);
        
        long sumA = 0, sumB = 0;
        int i=0, j=0;
        
        for (long itr : A){ // will return the sum of array A
            sumA += itr;
        }
            
        for (long itr  : B){ // will return the sum of array B
            sumB += itr;
        }
        
        while(i<n && j<m){
            //now subtract and add the current ele in the sumA and sumB and check euality.  
            long temp1 = sumA - A[i] + B[j];
            long temp2 = sumB - B[j] + A[i];
            
            if(temp1 == temp2){
                return 1;  // if both arrays sum is equal 
            }else if(temp1 > temp2){
                i++; //now if updated sumA(temp1) is > temp2 then increment iterator only for this.  
            }
            else{
                j++;
            }
        }
        
        return -1;
        
    }
}



// { Driver Code Starts.

// Driver class
class Array {

    // Driver code
    public static void main(String[] args) throws IOException {
        // Taking input using buffered reader
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        int testcases = Integer.parseInt(br.readLine());
        // looping through all testcases
        while (testcases-- > 0) {
            String line = br.readLine();
            String[] q = line.trim().split("\\s+");
            int n =Integer.parseInt(q[0]);
            int m =Integer.parseInt(q[1]);
            String line1 = br.readLine();
            String[] a1 = line1.trim().split("\\s+");
            long a[] = new long[n];
            for (int i = 0; i < n; i++) {
                a[i] = Long.parseLong(a1[i]);
            }
            String line2 = br.readLine();
            String[] a2 = line2.trim().split("\\s+");
            long b[] = new long[m];
            for (int i = 0; i < m; i++) {
                b[i] = Long.parseLong(a2[i]);
            }
            Solution ob = new Solution();
            long ans = ob.findSwapValues(a,n,b,m);
            System.out.println(ans);
        }
    }
}