import java.io.*;
 
public class Main
{
    public static void main(String[] args) throws IOException
    {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
 
        int tests = Integer.parseInt(br.readLine());
 
        while(tests-- > 0)
        {
            int a[] = new int[2];
            String line = br.readLine();
            String[] strs = line.trim().split("\\s+");
            for (int i=0; i<2; i++)
            {
                a[i] = Integer.parseInt(strs[i]);
            }
 
            System.out.println(2*a[0]*a[1]/(a[0]+a[1]));
        }
    }
}

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

Mgo1MCA1MAo2MCA0MA==

2
50 50
60 40