题号：NC223763
时间限制：C/C++/Rust/Pascal 1秒，其他语言2秒
空间限制：C/C++/Rust/Pascal 256 M，其他语言512 M
64bit IO Format: %lld
时间限制：C/C++/Rust/Pascal 1秒，其他语言2秒
空间限制：C/C++/Rust/Pascal 256 M，其他语言512 M
64bit IO Format: %lld
题目描述
little D and little Huan are playing a game, but this game is very metaphysical, without any player operation. At the beginning of the game, little D has 
bloods, little Huan has 
bloods. Each round of the game will randomly select one of the players and deduct a drop of blood. When a player's blood amount is 0, it represents the loss of the game. What is the probability of little D winning the game? Take the answer modulus of 998244353
输入描述:
The first row has two integers
输出描述:
A line with an integer represents the answer