#include #include using namespace std; class ModComb { long long *fact, *facti; const int mod; public: explicit ModComb(int n, int m) : mod(m) { fact = new long long[n+1]; facti = new long long[n+1]; fact[0] = 1; facti[0] = 1; for (int i = 1; i <= n; i++) fact[i] = (fact[i-1] * i) % m; // calc 1/n! long long &inv = facti[n], pw = fact[n]; inv = 1; for (int e = mod-2; e > 0; e /= 2) { if (e&1) inv = inv * pw % mod; pw = pw * pw % mod; } for (int i = n-1; i > 0; i--) facti[i] = (facti[i+1] * (i+1)) % m; } ~ModComb() { if (fact) delete[] fact; if (facti) delete[] facti; } long long getFact(int n) const { return fact[n]; } long long getFactInv(int n) const { return facti[n]; } long long getComb(int n, int k) const { if (n < 0 || k < 0 || k > n) return 0; return fact[n] * facti[k] % mod * facti[n-k] % mod; } long long getPerm(int n, int k) const { if (n < 0 || k < 0 || k > n) return 0; return fact[n] * facti[n-k] % mod; } }; long long modexp(int x, long long e, int m) { long long ans = 1, p = x % m; while (e > 0) { if (e % 2 != 0) ans = (ans * p) % m; p = (p * p) % m; e >>= 1; } return ans; } int main() { int n; cin >> n; long long ans = 0; constexpr int M = 998244353; ModComb mc(n, M); for (int k = 0; k <= n; k += 2) ans += 2 * mc.getComb(n, k) % M * modexp(2, abs(n-2*k), M) % M; cout << ans % M << endl; }