#[allow(unused_imports)] use std::cmp::{max, min}; #[allow(unused_imports)] use std::collections::{HashMap, HashSet}; mod util { use std::io::stdin; use std::str::FromStr; use std::fmt::Debug; #[allow(dead_code)] pub fn line() -> String { let mut line: String = String::new(); stdin().read_line(&mut line).unwrap(); line.trim().to_string() } #[allow(dead_code)] pub fn get() -> T where ::Err: Debug, { let mut line: String = String::new(); stdin().read_line(&mut line).unwrap(); line.trim().parse().unwrap() } #[allow(dead_code)] pub fn gets() -> Vec where ::Err: Debug, { let mut line: String = String::new(); stdin().read_line(&mut line).unwrap(); line.split_whitespace() .map(|t| t.parse().unwrap()) .collect() } #[allow(dead_code)] pub fn get2() -> (T, U) where ::Err: Debug, ::Err: Debug, { let mut line: String = String::new(); stdin().read_line(&mut line).unwrap(); let mut iter = line.split_whitespace(); ( iter.next().unwrap().parse().unwrap(), iter.next().unwrap().parse().unwrap(), ) } } #[allow(unused_macros)] macro_rules! debug { ($x: expr) => { println!("{}: {:?}", stringify!($x), $x) } } // (gcd, x, y) fn extgcd(a: i64, b: i64) -> (i64, i64, i64) { if b == 0 { (a, 1, 0) } else { let (gcd, x, y) = extgcd(b, a % b); (gcd, y, x - (a / b) * y) } } fn mod_pow(x: u64, n: u64, m: u64) -> u64 { let mut res = 1; let mut x = x; let mut n = n; while n > 0 { if n & 1 == 1 { res = (res * x) % m; } x = (x * x) % m; n = n >> 1; } res } fn mod_inverse(a: u64, m: u64) -> u64 { let (_, x, _) = extgcd(a as i64, m as i64); ((m as i64 + x) as u64 % m) % m } const M: u64 = 1000000007; fn main() { let n: u64 = util::get(); let m = 2 * n; let u = (1..m + 1).fold(1, |a, b| a * b % M); let b = mod_pow(2, n, M); println!("{}", u * mod_inverse(b, M) % M) }