#include using namespace std; using ll = long long; const int INF = 1e9 + 10; const ll INFL = 4e18; /* https://x.com/hamamu_kyopro/status/1839680787920322683 https://x.com/eco4kb/status/1839666741406011512 f(x)=(1+x)(1+x^2)(1+x^4)…(1+x^(2^(N-1)))として、 f(x)^2=g(x)h(x)(ただし、係数和が両方ともN)と因数分解する方法に帰着される。 */ /* from: https://potato167.github.io/po167_library */ #include #include template vector fpsMul(const vector &a, const vector &b) { return atcoder::convolution(a, b); } template vector fpsAdd(const vector &a, const vector &b) { vector res(max(a.size(), b.size())); for (int i = 0; i < res.size(); i++) { if (i < a.size()) res[i] += a[i]; if (i < b.size()) res[i] += b[i]; } return res; } template vector fpsSub(const vector &a, const vector &b) { vector res(max(a.size(), b.size())); for (int i = 0; i < res.size(); i++) { if (i < a.size()) res[i] += a[i]; if (i < b.size()) res[i] -= b[i]; } return res; } template vector fpsInv(vector f, int len = -1) { if (len == -1) len = f.size(); assert(f[0] != 0); vector g = {1 / f[0]}; int s = 1; while (s < len) { // g = 2g_s - f(g_s)^2 (mod x ^ (2 * s)) // g = g - (fg - 1)g // (fg - 1) = 0 (mod x ^ (s)) vector n_g(s * 2, 0); vector f_s(s * 2, 0); g.resize(s * 2); for (int i = 0; i < s * 2; i++) { if (int(f.size()) > i) f_s[i] = f[i]; n_g[i] = g[i]; } atcoder::internal::butterfly(g); atcoder::internal::butterfly(f_s); for (int i = 0; i < s * 2; i++) f_s[i] *= g[i]; atcoder::internal::butterfly_inv(f_s); T iz = 1 / (T)(s * 2); for (int i = s; i < s * 2; i++) f_s[i] *= iz; for (int i = 0; i < s; i++) f_s[i] = 0; atcoder::internal::butterfly(f_s); for (int i = 0; i < s * 2; i++) f_s[i] *= g[i]; atcoder::internal::butterfly_inv(f_s); for (int i = s; i < s * 2; i++) n_g[i] -= f_s[i] * iz; swap(n_g, g); s *= 2; } g.resize(len); return g; } template vector fpsCyclicConvolution(vector f, vector g) { atcoder::internal::butterfly(f); atcoder::internal::butterfly(g); for (int i = 0; i < (int)f.size(); i++) f[i] *= g[i]; atcoder::internal::butterfly_inv(f); T iz = (T)(1) / (T)(f.size()); for (int i = 0; i < (int)f.size(); i++) f[i] *= iz; return f; } template vector fpsIntegral(vector f) { if (f.empty()) return f; vector num_inv((int)f.size() + 1); num_inv[0] = 1; num_inv[1] = 1; auto m = T::mod(); for (int i = 2; i <= (int)f.size(); i++) num_inv[i] = (0 - num_inv[m % i]) * (T)(m / i); f.reserve((int)f.size() + 1); f.push_back(0); for (int i = (int)f.size() - 1; i > 0; i--) f[i] = f[i - 1] * num_inv[i]; f[0] = 0; return f; } template vector fpsDifferential(vector f) { if (f.empty()) return f; for (int i = 0; i < (int)f.size() - 1; i++) f[i] = f[i + 1] * (T)(i + 1); f.pop_back(); return f; } template vector fpsExp(vector f, int len = -1) { if (len == -1) len = f.size(); if (len == 0) return {}; if (len == 1) return {T(1)}; assert(!f.empty() && f[0] == 0); int s = 1; // simple vector g = {T(1)}; while (s < len) { // g' / g // A * B vector A = g, B = g; A = fpsDifferential(A); B = fpsInv(B, 2 * s); A.resize(2 * s); A = fpsCyclicConvolution(A, B); A.pop_back(); A = fpsIntegral(A); for (int i = 0; i < s; i++) A[i] = 0; for (int i = s; i < s * 2; i++) A[i] = (i < (int)f.size() ? f[i] : 0) - A[i]; // g_hat = g (1 - g + f) // g += B = g * A g.resize(2 * s); B = fpsCyclicConvolution(A, g); for (int i = s; i < s * 2; i++) g[i] = B[i]; s *= 2; } g.resize(len); return g; } template vector fpsLog(vector f, int len = -1) { if (len == -1) len = f.size(); if (len == 0) return {}; if (len == 1) return {T(0)}; assert(!f.empty() && f[0] == 1); vector res = atcoder::convolution(fpsDifferential(f), fpsInv(f, len)); res.resize(len - 1); return fpsIntegral(res); } template vector fpsPow(vector f, long long M, int len = -1) { if (len == -1) len = f.size(); vector res(len, 0); if (M == 0) { res[0] = 1; return res; } for (int i = 0; i < (int)f.size(); i++) { if (f[i] == 0) continue; if (i > (len - 1) / M) break; vector g((int)f.size() - i); T v = (T)(1) / (T)(f[i]); for (int j = i; j < (int)f.size(); j++) g[j - i] = f[j] * v; long long zero = i * M; if (i) len -= i * M; g = fpsLog(g, len); for (T &x : g) x *= M; g = fpsExp(g, len); v = (T)(1) / v; T c = 1; while (M) { if (M & 1) c = c * v; v = v * v; M >>= 1; } for (int i = 0; i < len; i++) res[i + zero] = g[i] * c; return res; } return res; } // in : DFT(v) (len(v) = z) // out : DFT(v) (len(v) = 2 * z) template void fpsExtend(vector &v) { int z = v.size(); T e = (T(atcoder::internal::primitive_root_constexpr(T::mod()))).pow(T::mod() / (2 * z)); auto cp = v; atcoder::internal::butterfly_inv(cp); T tmp = (T)(1) / (T)(z); for (int i = 0; i < z; i++) { cp[i] *= tmp; tmp *= e; } atcoder::internal::butterfly(cp); for (int i = 0; i < z; i++) v.push_back(cp[i]); } // s.t |v| = 2 ^ s (no assert) template void fpsPickEvenOdd(vector &v, int odd) { int z = v.size() / 2; T half = (T)(1) / (T)(2); if (odd == 0) { for (int i = 0; i < z; i++) v[i] = (v[i * 2] + v[i * 2 + 1]) * half; v.resize(z); } else { T e = (T(atcoder::internal::primitive_root_constexpr(T::mod()))).pow(T::mod() / (2 * z)); T ie = T(1) / e; vector es = {half}; while ((int)es.size() != z) { vector n_es((int)es.size() * 2); for (int i = 0; i < (int)es.size(); i++) { n_es[i * 2] = (es[i]); n_es[i * 2 + 1] = (es[i] * ie); } ie *= ie; swap(n_es, es); } for (int i = 0; i < z; i++) v[i] = (v[i * 2] - v[i * 2 + 1]) * es[i]; v.resize(z); } } // return [x^k] P(x) / Q(x) template T bostanMori(long long k, vector P, vector Q) { assert(!Q.empty() && Q[0] != 0); int z = 1; while (z < (int)max(P.size(), Q.size())) z *= 2; P.resize(z * 2, 0); Q.resize(z * 2, 0); atcoder::internal::butterfly(P); atcoder::internal::butterfly(Q); // fast while (k) { // Q(-x) vector Q_n(z * 2); for (int i = 0; i < z; i++) { Q_n[i * 2] = Q[i * 2 + 1]; Q_n[i * 2 + 1] = Q[i * 2]; } for (int i = 0; i < z * 2; i++) { P[i] *= Q_n[i]; Q[i] *= Q_n[i]; } fpsPickEvenOdd(P, k & 1); fpsPickEvenOdd(Q, 0); k /= 2; if (k == 0) break; fpsExtend(P); fpsExtend(Q); } T SP = 0, SQ = 0; for (int i = 0; i < z; i++) SP += P[i], SQ += Q[i]; return SP / SQ; } template // 0 = a[i] * c[0] + a[i - 1] * c[1] + a[i - 2] * c[2] + ... + a[i - d] * c[d] // a.size() + 1 == c.size() // c[0] = - 1 ? // return a[k] T kthLinear(long long k, vector a, vector c) { int d = a.size(); assert(d + 1 == int(c.size())); vector P = atcoder::convolution(a, c); P.resize(d); return bostanMori(k, P, c); } #include using mint = atcoder::modint998244353; int main() { int N; cin >> N; vector F(3); F[0] = F[1] = F[2] = 1; F = fpsPow(F, N, N + 1); mint ans = F[N]; ans--; ans /= 2; cout << ans.val() << endl; }