#include #include using namespace atcoder; #pragma GCC target("avx2") #pragma GCC optimize("O3") #pragma GCC optimize("unroll-loops") using namespace std; using ll=long long; using ld=long double; using ull=unsigned long long; using i128 = __int128_t; #define vs vector #define rep(i,n) for(ll i=0;i=0;i--) #define rep3(i,a,b) for(ll i=a;i<=ll(b);i++) #define rep4(i,a,b) for(ll i=a;i>=ll(b);i--) #define forv(i,V) for(const auto& i:V) #define all(x) x.begin(),x.end() #define fi first #define se second #define SIZE(x) int(x.size()) constexpr ll mod=998244353; //constexpr ll mod=1000000007; #define pi 3.14159265358979323 #define INF32 2147483647 #define INF64 9223372036854775807 #define faster ios::sync_with_stdio(false);std::cin.tie(nullptr) #define pii pair #define pll pair #define pb push_back #define eb emplace_back #define mp make_pair #define rev reverse #define vi vector #define vll vector #define vpi vector> #define vpll vector> #define vvi vector> #define vvll vector> #define prq priority_queue #define lb lower_bound #define ub upper_bound #define popcnt __builtin_popcountll #define TLE while(true); #define RE assert(false); #define MLE vector>> mle_mle(400,vector>(1000,vector(1000))); const string YESNO[2] = {"NO", "YES"}; const string YesNo[2] = {"No", "Yes"}; const string yesno[2] = {"no", "yes"}; #define rall(n) (n).rbegin(),(n).rend() #define INT(...) int __VA_ARGS__;scan(__VA_ARGS__) #define LL(...) ll __VA_ARGS__;scan(__VA_ARGS__) #define STR(...) string __VA_ARGS__;scan(__VA_ARGS__) #define CHR(...) char __VA_ARGS__;scan(__VA_ARGS__) #define DBL(...) double __VA_ARGS__;scan(__VA_ARGS__) #define LD(...) ld __VA_ARGS__;scan(__VA_ARGS__) template ostream &operator<<(ostream&os,const pair&p){os< istream &operator>>(istream&is,pair&p){is>>p.first>>p.second;return is;} template ostream &operator<<(ostream&os,const vector&v){for(auto it=v.begin();it!=v.end();){os<<*it<<((++it)!=v.end()?" ":"");}return os;} template istream &operator>>(istream&is,vector&v){for(T &in:v){is>>in;}return is;} void scan(){} template void scan(Head&head,Tail&... tail){cin>>head;scan(tail...);} template void print(const T &t){cout< void print(const Head &head, const Tail &... tail){cout< void fin(const T &... a){print(a...);exit(0);} ll max(int a,ll b){return max((ll)a,b);} ll max(ll a,int b){return max((ll)b,a);} ll min(int a,ll b){return min((ll)a,b);} ll min(ll a,int b){return min((ll)b,a);} //a以上b以下の個数 template ll RangeOK(ll a,ll b,vector &v){ return max(ub(all(v),b)-lb(all(v),a),0); } template vector compress(vector &X) { vector vals = X; sort(vals.begin(), vals.end()); vals.erase(unique(vals.begin(), vals.end()), vals.end()); for (int i = 0; i < (int)X.size(); i++) { X[i] = lower_bound(vals.begin(), vals.end(), X[i]) - vals.begin(); } return vals; } /* #include #include using namespace __gnu_pbds; */ const int MOD = 998244353; vector fact, fact_inv, inv; /* init_nCk :二項係数のための前処理 計算量:O(n) */ void init_nCk(int SIZE) { fact.resize(SIZE + 5); fact_inv.resize(SIZE + 5); inv.resize(SIZE + 5); fact[0] = fact[1] = 1; fact_inv[0] = fact_inv[1] = 1; inv[1] = 1; for (int i = 2; i < SIZE + 5; i++) { fact[i] = fact[i - 1] * i % MOD; inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD; fact_inv[i] = fact_inv[i - 1] * inv[i] % MOD; } } /* nCk :MODでの二項係数を求める(前処理 int_nCk が必要) 計算量:O(1) */ long long nCk(int n, int k) { if(n < k) return 0; if(n < 0 || k < 0) return 0; return fact[n] * (fact_inv[k] * fact_inv[n - k] % MOD) % MOD; } ll modpow(ll n, ll k){ ll ret = 1; while(k){ if(k&1) ret = ret*n%mod; n = n*n%mod; k >>= 1; } return ret; } ll n, m; ll f(ll a, ll b){ //print(a, b); if(abs(n)%2 != abs(a)%2) return 0; if(abs(n)%2 != abs(b)%2) return 0; ll p = (n+a)/2; ll q = (n+b)/2; //print(p, q); return nCk(n, p)*nCk(n, q)%mod; } int main(){ init_nCk(2000000); scan(n, m); ll ans = 0; for(ll i = 1; i*i <= abs(m); i++){ if(abs(m)%i == 0){ ans += f(i, m/i); ans += f(-i, -m/i); if(i != abs(m)/i){ ans += f(m/i, i); ans += f(-m/i, -i); } ans %= mod; } } if(m == 0){ ans += f(0, 0); rep3(i, 1, 2000000){ ans += f(0, i); ans %= mod; } rep3(i, 1, 2000000){ ans += f(0, -i); ans %= mod; } rep3(i, 1, 2000000){ ans += f(i, 0); ans %= mod; } rep3(i, 1, 2000000){ ans += f(-i, 0); ans %= mod; } } ll inv = 1; rep(i, n) inv = inv*4%mod; //print(ans, inv); inv = modpow(inv, mod-2); fin(ans*inv%mod); }