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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