#include #pragma GCC optimize("Ofast") #define _GLIBCXX_DEBUG using namespace std; using ll=long long; const ll mod=998244353; #define rep(i,a) for (ll i=0;i fact; std::vector rev; std::vector fact_rev; combination(int max,long long mod):upper(max),MOD(mod),fact(max+1),rev(max+1),fact_rev(max+1){ for(long long i=0;i<=max;i++){ if(i<2){ fact[i]=1; fact_rev[i]=1; rev[i]=1; continue; } fact[i]=(fact[i-1]*i)%mod; rev[i]=mod-((mod/i)*rev[mod%i])%mod; fact_rev[i]=(fact_rev[i-1]*rev[i])%mod; } } long long Comb(int x,int y){ assert(upper>=x); if (x>t; rep(i,t) solve(); } void solve(){ ll N,K; cin>>N>>K; combination table(N*3,mod); vector sum(2*N+1,1); rep(i,N*2){ sum[i+1]=(sum[i]+table.Comb(N*2,i+1))%mod; } auto f=[&](ll L)->ll{ ll ans=(L*table.Comb(N*2,N))%mod; for(int i=1;i<=N;i++){ if(i%L==0){ ans+=(2ll*(L-1)*table.Comb(2*N,N-i))%mod; }else{ ans-=2ll*table.Comb(2*N,N-i); } } ans=(ans+mod)%mod; return ans; }; cout<<(table.Comb(N*2,N)-f(K+1)+f(K)+mod)%mod<<"\n"; }