CF272D Dima and Two Sequences
Description
Little Dima has two sequences of points with integer coordinates: sequence $ (a_{1},1),(a_{2},2),...,(a_{n},n) $ and sequence $ (b_{1},1),(b_{2},2),...,(b_{n},n) $ .
Now Dima wants to count the number of distinct sequences of points of length $ 2·n $ that can be assembled from these sequences, such that the $ x $ -coordinates of points in the assembled sequence will not decrease. Help him with that. Note that each element of the initial sequences should be used exactly once in the assembled sequence.
Dima considers two assembled sequences $ (p_{1},q_{1}),(p_{2},q_{2}),...,(p_{2·n},q_{2·n}) $ and $ (x_{1},y_{1}),(x_{2},y_{2}),...,(x_{2·n},y_{2·n}) $ distinct, if there is such $ i $ $ (1
Input Format
The first line contains integer $ n $ $ (1
Output Format
In the single line print the remainder after dividing the answer to the problem by number $ m $ .
Explanation/Hint
In the first sample you can get only one sequence: $ (1,1),(2,1) $ .
In the second sample you can get such sequences : $ (1,1),(2,2),(2,1),(3,2) $ ; $ (1,1),(2,1),(2,2),(3,2) $ . Thus, the answer is $ 2 $ .