#include #define pb push_back #define eb emplace_back #define fi first #define se second #define rep(i,N) for(long long i = 0; i < (long long)(N); i++) #define repr(i,N) for(long long i = (long long)(N) - 1; i >= 0; i--) #define rep1(i,N) for(long long i = 1; i <= (long long)(N) ; i++) #define repr1(i,N) for(long long i = (N) ; (long long)(i) > 0 ; i--) #define each(x,v) for(auto& x : v) #define all(v) (v).begin(),(v).end() #define sz(v) ((int)(v).size()) #define ini(...) int __VA_ARGS__; in(__VA_ARGS__) #define inl(...) long long __VA_ARGS__; in(__VA_ARGS__) #define ins(...) string __VA_ARGS__; in(__VA_ARGS__) using namespace std; void solve(); using ll = long long; template using V = vector; using vi = V; using vl = V<>; using vvi = V< V >; constexpr int inf = 1001001001; constexpr ll infLL = (1LL << 61) - 1; struct IoSetupNya {IoSetupNya() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); cerr << fixed << setprecision(7);} } iosetupnya; template inline bool amin(T &x, U y) { return (y < x) ? (x = y, true) : false; } template inline bool amax(T &x, U y) { return (x < y) ? (x = y, true) : false; } template ostream& operator <<(ostream& os, const pair &p) { os << p.first << " " << p.second; return os; } template istream& operator >>(istream& is, pair &p) { is >> p.first >> p.second; return is; } template ostream& operator <<(ostream& os, const vector &v) { int s = (int)v.size(); rep(i,s) os << (i ? " " : "") << v[i]; return os; } template istream& operator >>(istream& is, vector &v) { for(auto &x : v) is >> x; return is; } void in(){} template void in(T &t,U &...u){ cin >> t; in(u...);} void out(){cout << "\n";} template void out(const T &t,const U &...u){ cout << t; if(sizeof...(u)) cout << " "; out(u...);} templatevoid die(T x){out(x); exit(0);} #ifdef NyaanDebug #include "NyaanDebug.h" #define trc(...) do { cerr << #__VA_ARGS__ << " = "; dbg_out(__VA_ARGS__);} while(0) #define trca(v,N) do { cerr << #v << " = "; array_out(v , N);cout << endl;} while(0) #else #define trc(...) #define trca(...) int main(){solve();} #endif using P = pair; using vp = V

; constexpr int MOD = /**/ 1000000007; //*/ 998244353; ////////// template< int mod > 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 >; using vm = vector; // BIT template< typename T > struct BIT { int N; int max_2beki; vector< T > data; // 初期化 1-indexedでデータを管理する 0で初期化 BIT(int size){ N = ++size; data.assign(N, 0); max_2beki = 1; while(max_2beki * 2 <= N) max_2beki *= 2; } // [0,k](閉区間)の総和 閉区間に注意! T sum(int k) { if(k < 0) return 0; // k<0のとき0を返す T ret = 0; for(++k; k > 0; k -= k & -k) ret += data[k]; return (ret); } // [l,r](閉区間)の総和 inline T sum(int l,int r){ return sum(r) - sum(l-1); } // 一点取得 更新はできないことに注意 inline T operator[](int k){ return sum(k) - sum(k-1); } // data[k] += x; void add(int k, T x) { for(++k; k < N; k += k & -k) data[k] += x; } // imos法 [l,r]にxを加算 void imos(int l,int r,T x){ add(l , x); add(r + 1 , -x); } // lower_bound sum(i)がval以上となる最小のi int lower_bound(T w){ if(w <= 0) return 0; int x = 0; for(int k = max_2beki; k > 0; k /= 2){ if(x+k <= N - 1 && data[x + k] < w){ w -= data[x + k]; x += k; } } return x; } // upper_bound sum(i)がvalより大きくなる最小のi int upper_bound(T w){ if(w < 0) return 0; int x = 0; for(int k = max_2beki; k > 0; k /= 2){ if(x+k <= N - 1 && data[x + k] <= w){ w -= data[x + k]; x += k; } } return x; } }; V> dp(2048 , 2048); void solve(){ ini(N); if(N <= 2) die(0); dp[1].add(1 , 1); for(int i = 2 ; i <= N ; i++) for(int j = 1 ; j <= i ; j++){ if(i % 2 == 0) dp[i].add(j , dp[i - 1].sum(1 , j - 1)); else dp[i].add(j , dp[i - 1].sum(j , i - 1)); } out(dp[N].sum(1 , N) * 2); }