1721. Rikka with Rock-paper-scissors

时间限制 8000 ms   内存限制 64 MB

As we know, Rikka is poor at math. Yuta is worrying about this situation, so he gives Rikka some math tasks to practice. There is one of them:

Alice and Bob are going to play a famous game: Rock-paper-scissors. Both of them don't like to think a lot, so both of them will use the random strategy: choose rock/paper/scissors in equal probability.

They want to play this game $n$ times, then they will calculate the score $s$ in the following way: if Alice wins $a$ times, Bob wins $b$ times, and in the remaining $n-a-b$ games they make a tie, the score will be the greatest common divisor of $a$ and $b$.

Know Yuta wants to know the expected value of $s \times 3^{2n}$. It is easy to find that the answer must be an integer.

It is too difficult for Rikka. Can you help her?

Note: If one of $a,b$ is $0$, we define the greatest common divisor of $a$ and $b$ as $a+b$.

输入数据

The first line contains a number $t(1 \leq t \leq 20)$, the number of the testcases. There are no more than $2$ testcases with $n \geq 10^4$.

For each testcase, the first line contains two numbers $n,mo(1 \leq n \leq 10^5, 10^8 \leq mo \leq 10^9)$

It is guaranteed that $mo$ is a prime number.

输出数据

For each testcase, print a single line with a single number -- the answer modulo $mo$.

样例输入

复制
5
1 998244353
2 998244353
3 998244353
4 998244353
5 998244353 \n
 ·         \n
 ·         \n
 ·         \n
 ·         \n
 ·         \n

样例输出

复制
6
90
972
9720
89910 \n
  \n
   \n
    \n
     \n

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Source

2017 Multi-University Training Contest - Team 5

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