#include #include using namespace std; using namespace atcoder; //using mint = modint1000000007; //const int mod = 1000000007; using mint = modint998244353; const int mod = 998244353; //const int INF = 1e9; //const long long LINF = 1e18; #define rep(i, n) for (int i = 0; i < (n); ++i) #define rep2(i,l,r)for(int i=(l);i<(r);++i) #define rrep(i, n) for (int i = (n-1); i >= 0; --i) #define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i) #define all(x) (x).begin(),(x).end() #define allR(x) (x).rbegin(),(x).rend() #define endl "\n" #define P pair template inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; } template inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; } // combination mod prime // https://www.youtube.com/watch?v=8uowVvQ_-Mo&feature=youtu.be&t=1619 struct combination { vector fact, ifact; combination(int n) :fact(n + 1), ifact(n + 1) { assert(n < mod); fact[0] = 1; for (int i = 1; i <= n; ++i) fact[i] = fact[i - 1] * i; ifact[n] = fact[n].inv(); for (int i = n; i >= 1; --i) ifact[i - 1] = ifact[i] * i; } mint operator()(int n, int k) { return com(n, k); } mint com(int n, int k) { //負の二項係数を考慮する場合にコメントアウトを外す //if (n < 0) return com(-n, k) * (k % 2 ? -1 : 1); if (k < 0 || k > n) return 0; return fact[n] * ifact[k] * ifact[n - k]; } mint comsub(long long n, long long k) { if (n - k < k) k = n - k; assert(k < (int)fact.size()); mint val = ifact[k]; rep(i, k) val *= n - i; return val; } mint div(int x) { if (x >= (int)fact.size())return mint(x).inv(); return fact[x - 1] * ifact[x]; } mint inv(int n, int k) { //if (n < 0) return inv(-n, k) * (k % 2 ? -1 : 1); if (k < 0 || k > n) return 0; return ifact[n] * fact[k] * fact[n - k]; } mint p(int n, int k) { return fact[n] * ifact[n - k]; } }c(2000006); int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int n; cin >> n; long long m; cin >> m; mapmp; rep(i, n + 1) { mp[((long long)i) * i] = i; } mint ans = 0; rep(i, n + 1) { long long x = (long long)i * i; long long y = x - m; if (!mp.count(y))continue; int j = mp[y]; if (n % 2 != (i + j) % 2)continue; mint sub = 0; sub = c(n, (n + i - j) / 2) * c(n, (n - i - j) / 2); if (0 != i)sub *= 2; if (0 != j)sub *= 2; ans += sub; } ans /= pow_mod(4, n, mod); cout << ans.val() << endl; return 0; }