import java.util.*;
import java.lang.*;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
class Main
{
{
int ile
= Integer.
parseInt(br.
readLine());
for (int j=0; j < ile; j++) {
int a[] = new int[2];
String[] s
= line.
trim().
split(" "); for (int i = 0; i < 2; i++) {
}
System.
out.
println(2 * a
[0] * a
[1] / (a
[0] + a
[1])); }
}
}
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