#include<iostream>
#include<cassert>
#include "inv.h"
using ll=long long;
constexpr ll mod=998244353;
void init(int p){
  assert(p==mod);
}
int inv(int x){
  ll res=1;
  ll p=mod-2;
  while(p){
    if(p&1)res=res*x%mod;
    x=ll(x)*x%mod;
    p>>=1;
  }
  return res;
}