AT_arc203_a [ARC203A] All Winners
Description
$ N $ teams are participating in a team shogi tournament. Each team consists of $ M $ players. This tournament is a round-robin format, with a total of $ \frac{N(N-1)}{2} $ matches played. In each match, the $ M $ players from each team are randomly matched against each other, and one player always wins while the other loses. After all matches are played, each player will have played exactly $ N-1 $ games, and players who won all their games will be awarded the perfect record prize. Find the maximum possible number of players who can be awarded the perfect record prize.
Solve $ T $ test cases for each input file.
Input Format
The input is given from Standard Input in the following format:
> $ T $ $ case_1 $ $ case_2 $ $ \vdots $ $ case_T $
Each case is given in the following format:
> $ N $ $ M $
Output Format
Output the answers in a total of $ T $ lines. The $ t $ -th line should contain the maximum possible number of players who can be awarded the perfect record prize for the $ t $ -th test case.
Explanation/Hint
### Sample Explanation 1
For the first test case, suppose the following $ 3 $ teams participate in the tournament:
Team $ T $ : players $ T_1,T_2,T_3 $
Team $ W $ : players $ W_1,W_2,W_3 $
Team $ R $ : players $ R_1,R_2,R_3 $
and suppose the following results occur:
- Match between Team $ T $ and Team $ W $
- Game between $ T_1 $ and $ W_1 $ : $ W_1 $ wins
- Game between $ T_2 $ and $ W_2 $ : $ W_2 $ wins
- Game between $ T_3 $ and $ W_3 $ : $ T_3 $ wins
- Match between Team $ T $ and Team $ R $
- Game between $ T_1 $ and $ R_3 $ : $ T_1 $ wins
- Game between $ T_2 $ and $ R_1 $ : $ R_1 $ wins
- Game between $ T_3 $ and $ R_2 $ : $ T_3 $ wins
- Match between Team $ W $ and Team $ R $
- Game between $ W_1 $ and $ R_3 $ : $ R_3 $ wins
- Game between $ W_2 $ and $ R_2 $ : $ R_2 $ wins
- Game between $ W_3 $ and $ R_1 $ : $ W_3 $ wins
Then, only player $ T_3 $ from Team $ T $ is awarded the perfect record prize.
In this case, the maximum possible number of players who can be awarded the perfect record prize is $ 4 $ .
### Constraints
- $ 1 \leq T \leq 2 \times 10^5 $
- $ 2 \leq N \leq 10^9 $
- $ 1 \leq M \leq 10^9 $
- All input values are integers.