#include "bits/stdc++.h" using namespace std; #ifdef _DEBUG #include "dump.hpp" #else #define dump(...) #endif #define int long long #define rep(i,a,b) for(int i=(a);i<(b);i++) #define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--) #define all(c) begin(c),end(c) const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f; const int MOD = (int)(1e9) + 7; const double PI = acos(-1); const double EPS = 1e-9; template bool chmax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; } template bool chmin(T &a, const T &b) { if (a > b) { a = b; return true; } return false; } //by anta //20160723 //http://arc058.contest.atcoder.jp/submissions/815261 template struct ModInt { static const int Mod = MOD; unsigned x; ModInt() : x(0) {} ModInt(signed sig) { int sigt = sig % MOD; if (sigt < 0) sigt += MOD; x = sigt; } ModInt(signed long long sig) { int sigt = sig % MOD; if (sigt < 0) sigt += MOD; x = sigt; } int get() const { return (int)x; } ModInt &operator+=(ModInt that) { if ((x += that.x) >= MOD) x -= MOD; return *this; } ModInt &operator-=(ModInt that) { if ((x += MOD - that.x) >= MOD) x -= MOD; return *this; } ModInt &operator*=(ModInt that) { x = (unsigned long long)x * that.x % MOD; return *this; } ModInt &operator/=(ModInt that) { return *this *= that.inverse(); } ModInt operator+(ModInt that) const { return ModInt(*this) += that; } ModInt operator-(ModInt that) const { return ModInt(*this) -= that; } ModInt operator*(ModInt that) const { return ModInt(*this) *= that; } ModInt operator/(ModInt that) const { return ModInt(*this) /= that; } ModInt inverse() const { signed a = x, b = MOD, u = 1, v = 0; while (b) { signed t = a / b; a -= t * b; std::swap(a, b); u -= t * v; std::swap(u, v); } if (u < 0) u += MOD; ModInt res; res.x = (unsigned)u; return res; } }; template ostream &operator << (ostream &os, const ModInt &m) { return os << m.x; } template istream &operator >> (istream &is, ModInt &m) { signed long long s; is >> s; m = ModInt(s); return is; }; template ModInt operator^(ModInt a, unsigned long long k) { ModInt r = 1; while (k) { if (k & 1) r *= a; a *= a; k >>= 1; } return r; } using mint = ModInt<1000000007>; //nCrで用いる vector fact, factinv; //nCrで用いる 予め計算しておく void nCr_compute_factinv(int N) { N = min(N, mint::Mod - 1); fact.resize(N + 1); factinv.resize(N + 1); fact[0] = 1; rep(i, 1, N + 1) fact[i] = fact[i - 1] * i; factinv[N] = fact[N].inverse(); for (int i = N; i >= 1; i--) factinv[i - 1] = factinv[i] * i; } mint nCr(int n, int r) { if (n >= mint::Mod) return nCr(n % mint::Mod, r % mint::Mod) * nCr(n / mint::Mod, r / mint::Mod); return r > n ? 0 : fact[n] * factinv[n - r] * factinv[r]; } int mod_pow(int x, int n) { int res(1); while (n > 0) { if (n & 1)res = res*x%MOD; x = x*x%MOD; n >>= 1; } return res; } signed main() { cin.tie(0); ios::sync_with_stdio(false); int N; cin >> N; vector>f(2 * N + 1); f[0] = 1; rep(i, 1, f.size())f[i] = (f[i - 1] * i); ModInt ans(f[2 * N]); ans /= mod_pow(2, N); cout << ans << endl; return 0; }