#include using namespace std; typedef long long ll; const int mod=1e9+7; const int nmax=3; ll fac[nmax],finv[nmax],inv[nmax]; void COMinit(){ fac[0]=fac[1]=1; finv[0]=finv[1]=1; inv[1]=1; for(int i=2;i> n; COMinit(); ll ans=1; for(ll i=1;i<=2*n;i++){ ans*=i; ans%=mod; if(i%2==0){ ans*=inv[2]; ans%=mod; } } cout << ans << endl; }