#include #include #include using namespace std; using ll = long long; constexpr ll MOD = 1000000007; struct Combination{ using ll = long long; const int n; vector fac, ifac; ll mp(ll a, ll x) const { ll res = 1; for(; x > 0; x >>= 1){ if(x&1){ res *= a; res %= MOD; } a *= a; a %= MOD; } return res; } Combination(int _n = 1000000): n(_n), fac(vector(_n+1)), ifac(vector(_n+1)){ fac[0] = 1; for(int i = 1; i <= n; i++) fac[i] = (fac[i-1]*i)%MOD; ifac[n] = mp(fac[n], MOD-2); for(int i = n; i > 0; i--) ifac[i-1] = (ifac[i]*i)%MOD; } ll operator()(int n, int k) const { if (k < 0 || k > n) return 0; return fac[n]*ifac[k]%MOD*ifac[n-k]%MOD; } }; int main(){ int n; cin >> n; Combination comb{n*2+10}; ll ans = comb.fac[n*2]; for(int i = 0; i < n; i++){ ans *= comb.ifac[2]; ans %= MOD; } cout << ans << endl; return 0; }