#include using namespace std; #define overload2(a, b, c, ...) c #define overload3(a, b, c, d, ...) d #define overload4(a, b, c, d, e ...) e #define overload5(a, b, c, d, e, f ...) f #define overload6(a, b, c, d, e, f, g ...) g #define fast_io ios::sync_with_stdio(false); cin.tie(nullptr); #pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math") typedef long long ll; typedef long double ld; #define chmin(a,b) a = min(a,b); #define chmax(a,b) a = max(a,b); #define bit_count(x) __builtin_popcountll(x) #define leading_zero_count(x) __builtin_clz(x) #define trailing_zero_count(x) __builtin_ctz(x) #define gcd(a,b) __gcd(a,b) #define lcm(a,b) a / gcd(a,b) * b #define rep(...) overload3(__VA_ARGS__, rrep, rep1)(__VA_ARGS__) #define rep1(i,n) for(int i = 0 ; i < n ; i++) #define rrep(i,a,b) for(int i = a ; i < b ; i++) #define repi(it,S) for(auto it = S.begin() ; it != S.end() ; it++) #define pt(a) cout << a << endl; #define print(...) printall(__VA_ARGS__); #define debug(a) cout << #a << " " << a << endl; #define all(a) a.begin(), a.end() #define endl "\n"; #define v1(T,n,a) vector(n,a) #define v2(T,n,m,a) vector>(n,v1(T,m,a)) #define v3(T,n,m,k,a) vector>>(n,v2(T,m,k,a)) #define v4(T,n,m,k,l,a) vector>>>(n,v3(T,m,k,l,a)) templateistream &operator>>(istream&is,pair&p){is>>p.first>>p.second;return is;} templateostream &operator<<(ostream&os,const pair&p){os<istream &operator>>(istream&is,vector&v){for(T &in:v){is>>in;}return is;} templateostream &operator<<(ostream&os,const vector&v){for(auto it=v.begin();it!=v.end();){os<<*it<<((++it)!=v.end()?" ":"");}return os;} templateistream &operator>>(istream&is,vector>&v){for(T &in:v){is>>in;}return is;} templateostream &operator<<(ostream&os,const vector>&v){for(auto it=v.begin();it!=v.end();){os<<*it<<((++it)!=v.end()?"\n":"");}return os;} templateostream &operator<<(ostream&os,const set&v){for(auto it=v.begin();it!=v.end();){os<<*it<<((++it)!=v.end()?" ":"");}return os;} templateostream &operator<<(ostream&os,const multiset&v){for(auto it=v.begin();it!=v.end();){os<<*it<<((++it)!=v.end()?" ":"");}return os;} template void printall(Args... args){for(auto i:initializer_list>{args...}) cout< struct ModInt { int x; ModInt() : x(0) {} ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {} ModInt &operator+=(const ModInt &p) { if((x += p.x) >= mod) x -= mod; return *this; } ModInt &operator-=(const ModInt &p) { if((x += mod - p.x) >= mod) x -= mod; return *this; } ModInt &operator*=(const ModInt &p) { x = (int) (1LL * x * p.x % mod); return *this; } ModInt &operator/=(const ModInt &p) { *this *= p.inverse(); return *this; } ModInt operator-() const { return ModInt(-x); } ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; } ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; } ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; } ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; } bool operator==(const ModInt &p) const { return x == p.x; } bool operator!=(const ModInt &p) const { return x != p.x; } ModInt inverse() const { int a = x, b = mod, u = 1, v = 0, t; while(b > 0) { t = a / b; swap(a -= t * b, b); swap(u -= t * v, v); } return ModInt(u); } ModInt pow(int64_t n) const { ModInt ret(1), mul(x); while(n > 0) { if(n & 1) ret *= mul; mul *= mul; n >>= 1; } return ret; } friend ostream &operator<<(ostream &os, const ModInt &p) { return os << p.x; } friend istream &operator>>(istream &is, ModInt &a) { int64_t t; is >> t; a = ModInt< mod >(t); return (is); } static int get_mod() { return mod; } }; using modint = ModInt< mod >; const int MAX_N = 3030303; modint inv[MAX_N+1] ; // (n!)^(p-2) (mod p) を格納 modint fac[MAX_N+1] ; // (n!) (mod p) を格納 modint powmod(modint x , ll n){ modint res = 1 ; while(n > 0){ if(n & 1) res *= x; x *= x; n >>= 1 ; } return res ; } // 階乗の逆元(n!)^(-1)のmodを配列に格納 void f(){ inv[0] = 1 ; inv[1] = 1 ; for(ll i = 2 ; i <= MAX_N ; i++){ inv[i] = powmod(i,mod-2) * inv[i-1]; } } // 階乗のmodを配列に格納 void g(){ fac[0] = 1 ; fac[1] = 1 ; for(ll i = 2 ; i <= MAX_N ; i++){ fac[i] = fac[i-1] * i; } } //nCrの計算 modint combination(ll n , ll r){ if(n < 0 || r < 0 || n < r) return 0 ; return fac[n] * inv[n-r] * inv[r]; } modint permutation(ll n , ll r){ if(n < 0 || r < 0 || n < r) return 0 ; return fac[n] * inv[n-r]; } void init(){ f() ; g() ; } struct NTT{ private: int n , logn = 0; modint BASE = 3 ; vector vec , X , Y ; vector> ROOT , INV_ROOT ; // ビルドする(畳み込み→逆変換) void build(){ // 畳み込み vector V = convolution(X,Y) ; // 逆変換 vec = ifft(V) ; } // バタフライ演算を行うために配置を変換 inline void arrangeIndexForBatafly(vector &A , int logn){ for (int i = 0; i < n; i++) { int j = 0; for (int k = 0; k < logn; k++) j |= (i >> k & 1) << (logn - 1 - k); if (i < j) swap(A[i], A[j]); } } // FFT, IFFT のロジック inline vector sub_fft(vector A , bool inverse){ // バタフライ演算 arrangeIndexForBatafly(A,logn) ; int lg = 1 ; for(int block = 1 ; block < n ; block *= 2){ // block内 の j 番目に対する処理 for(int j = 0 ; j < block ; j++){ // w , v : 重み modint w = inverse ? ROOT[lg][j] : INV_ROOT[lg][j] ; modint v = inverse ? ROOT[lg][j+block] : INV_ROOT[lg][j+block] ; for(int i = 0 ; i < n ; i += 2 * block){ modint s = A[j+i] ; modint t = A[j+i+block] ; A[j + i] = s + t * w ; A[j + i + block] = s + t * v ; } } lg++ ; } if(inverse) for(int i = 0 ; i < n ; i++) A[i] /= n ; return A ; } // 高速数論変換(NTT) inline vector fft(vector A) { return sub_fft(A,false) ; } // 逆高速数論変換(INTT) inline vector ifft(vector A) { return sub_fft(A,true) ; } // 畳み込み(Comvolution)を行う inline vector convolution(vector A , vector B){ X = fft(A) , Y = fft(B) ; vector V(n,0) ; for(int i = 0 ; i < n ; i++) V[i] = X[i] * Y[i] ; return V ; } public: NTT(vector A , vector B){ BASE = BASE.pow(119) ; int n1 = A.size() , n2 = B.size() , n_ = n1 + n2 - 1 ; n = 1 ; while(n < n_) n *= 2 , logn++ ; X.resize(n,0) , Y.resize(n,0) ; for(int i = 0 ; i < n1 ; i++) X[i] = A[i] ; for(int i = 0 ; i < n2 ; i++) Y[i] = B[i] ; rep(i,logn+1) { vector pwr , ipwr ; modint POW = BASE.pow(1<<(23-i)) ; modint INV_POW = POW.inverse() ; modint powval = 1 , inv_powval = 1 ; rep(j,(1< get_fft() { return vec ; } }; ll n, m; void solve(){ init(); cin >> n >> m; m = abs(m); vector V; for(ll x = 1; x * x <= m; x++){ if(m % x != 0) continue; V.push_back(x); } modint res = 0; for(ll b : V){ ll a = m / b; if((a + b) % 2 != 0) continue; ll x = (a + b) / 2; ll y = (a - b) / 2; x = abs(x); y = abs(y); ll diff = n - (x + y); if(diff < 0) continue; if((n+x-y)%2) continue; if((n-x-y)%2) continue; modint t = 4; if(x == 0) t /= 2; if(y == 0) t /= 2; res += combination(n,(n+x-y)/2) * combination(n,(n-x-y)/2) * t; } pt(res / powmod(4,n)) } int main(){ // fast_io int t = 1; // cin >> t; rep(i,t) solve(); }