func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 200005, MOD = 1e9 + 7;   long long fact[N], inv[N];   long long qpow(long long a, int b) {     long long ans = 1;     do {       if (b & 1) ans = ans * a % MOD;       a = a * a % MOD;     } while (b /= 2);     return ans;   }   int main() {     int n;     cin >> n;     fact[0] = 1;     for (int i = 1; i <= n * 2; i++) fact[i] = fact[i - 1] * i % MOD;     inv[n * 2] = qpow(fact[n * 2], MOD - 2);     for (int i = n * 2 - 1; i >= 0; i--) inv[i] = inv[i + 1] * (i + 1) % MOD;     long long ans = 0;     for (int i = 0; i < n; i++)       ans += fact[n - 1 + i] * inv[n - 1] % MOD * inv[i] % MOD;     cout << (ans * 2 - n) % MOD << endl;     return 0;   }   