use std::io::stdin; const MOD: usize = 1_000_000_007; fn main() { let mut line = String::new(); stdin().read_line(&mut line).unwrap(); let n = line.trim().parse::().unwrap(); /* f[0] even = 1 // empty f[0] odd = 0 f[1] even = 24 // without SC f[1] odd = 2 // with SC f[2] even = f[1] even * 24 + f[1] odd * 2 f[2] odd = f[1] even * 2 + f[1] odd * 24 */ let mut f0e = 1; let mut f0i = 0; let mut f1e = 24; let mut f1i = 2; for _ in 2..=n { let f2e = (f1e * 24 + f1i * 2) % MOD; let f2i = (f1e * 2 + f1i * 24) % MOD; f0e = f1e; f0i = f1i; f1e = f2e; f1i = f2i; } println!("{}", f1e); }