AT_arc192_d [ARC192D] Fraction Line
Description
For a positive rational number $ x $ , define $ f(x) $ as follows:
> Express $ x $ as $ \dfrac{P}{Q} $ using coprime positive integers $ P $ and $ Q $ . $ f(x) $ is defined as the value $ P\times Q $ .
You are given a positive integer $ N $ and a sequence $ A=(A_1,A_2,\dots,A_{N-1}) $ of positive integers of length $ N-1 $ .
We call a sequence $ S=(S_1,S_2,\dots,S_N) $ of positive integers of length $ N $ a **good sequence** if it satisfies all of the following conditions:
- For every integer $ i $ with $ 1\leq i\leq N-1 $ , it holds that $ f\left(\dfrac{S_i}{S_{i+1}}\right)=A_i $ .
- $ \gcd(S_1,S_2,\dots,S_N)=1 $ .
Define the **score** of a sequence as the product of all its elements.
It can be proved that there are finitely many good sequences. Find the sum, modulo $ 998244353 $ , of the scores of all good sequences.
Input Format
The input is given from Standard Input in the following format:
> $ N $ $ A_1 $ $ A_2 $ $ \dots $ $ A_{N-1} $
Output Format
Print the sum, modulo $ 998244353 $ , of the scores of all good sequences.
Explanation/Hint
### Sample Explanation 1
For example, both $ (2,2,18,9,18,2) $ and $ (18,18,2,1,2,18) $ are good sequences, and both have a score of $ 23328 $ .
There are a total of $ 16 $ good sequences, and the sum of the scores of all of them is $ 939634344 $ .
### Sample Explanation 2
There are $ 2 $ good sequences, both with a score of $ 9 $ .
### Sample Explanation 3
Do not forget to compute the sum modulo $ 998244353 $ .
### Constraints
- $ 2\leq N\leq 1000 $
- $ 1\leq A_i\leq 1000 $ $ (1\leq i\leq N-1) $
- All input values are integers.