use std::io::Read; fn get_word() -> String { let stdin = std::io::stdin(); let mut stdin=stdin.lock(); let mut u8b: [u8; 1] = [0]; loop { let mut buf: Vec = Vec::with_capacity(16); loop { let res = stdin.read(&mut u8b); if res.unwrap_or(0) == 0 || u8b[0] <= b' ' { break; } else { buf.push(u8b[0]); } } if buf.len() >= 1 { let ret = String::from_utf8(buf).unwrap(); return ret; } } } fn get() -> T { get_word().parse().ok().unwrap() } /// Verified by https://atcoder.jp/contests/arc093/submissions/3968098 mod mod_int { use std::ops::*; pub trait Mod: Copy { fn m() -> i64; } #[derive(Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord)] pub struct ModInt { pub x: i64, phantom: ::std::marker::PhantomData } impl ModInt { // x >= 0 pub fn new(x: i64) -> Self { ModInt::new_internal(x % M::m()) } fn new_internal(x: i64) -> Self { ModInt { x: x, phantom: ::std::marker::PhantomData } } pub fn pow(self, mut e: i64) -> Self { debug_assert!(e >= 0); let mut sum = ModInt::new_internal(1); let mut cur = self; while e > 0 { if e % 2 != 0 { sum *= cur; } cur *= cur; e /= 2; } sum } #[allow(dead_code)] pub fn inv(self) -> Self { self.pow(M::m() - 2) } } impl>> Add for ModInt { type Output = Self; fn add(self, other: T) -> Self { let other = other.into(); let mut sum = self.x + other.x; if sum >= M::m() { sum -= M::m(); } ModInt::new_internal(sum) } } impl>> Sub for ModInt { type Output = Self; fn sub(self, other: T) -> Self { let other = other.into(); let mut sum = self.x - other.x; if sum < 0 { sum += M::m(); } ModInt::new_internal(sum) } } impl>> Mul for ModInt { type Output = Self; fn mul(self, other: T) -> Self { ModInt::new(self.x * other.into().x % M::m()) } } impl>> AddAssign for ModInt { fn add_assign(&mut self, other: T) { *self = *self + other; } } impl>> SubAssign for ModInt { fn sub_assign(&mut self, other: T) { *self = *self - other; } } impl>> MulAssign for ModInt { fn mul_assign(&mut self, other: T) { *self = *self * other; } } impl Neg for ModInt { type Output = Self; fn neg(self) -> Self { ModInt::new(0) - self } } impl ::std::fmt::Display for ModInt { fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result { self.x.fmt(f) } } impl ::std::fmt::Debug for ModInt { fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result { self.x.fmt(f) } } impl From for ModInt { fn from(x: i64) -> Self { Self::new(x) } } } // mod mod_int macro_rules! define_mod { ($struct_name: ident, $modulo: expr) => { #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)] struct $struct_name {} impl mod_int::Mod for $struct_name { fn m() -> i64 { $modulo } } } } const MOD: i64 = 998_244_353; define_mod!(P, MOD); type MInt = mod_int::ModInt

; // https://en.wikipedia.org/wiki/Berlekamp%E2%80%93Massey_algorithm // Depends on MInt.rs fn berlekamp_massey( n: usize, s: &[mod_int::ModInt

], ) -> Vec>{ type MInt

= mod_int::ModInt

; let mut b = MInt::new(1); let mut cp = vec![MInt::new(0); n + 1]; let mut bp = vec![mod_int::ModInt::new(0); n]; cp[0] = mod_int::ModInt::new(1); bp[0] = mod_int::ModInt::new(1); let mut m = 1; let mut l = 0; for i in 0..2 * n + 1 { assert!(i >= l); assert!(l <= n); if i == 2 * n { break; } let mut d = s[i]; for j in 1..l + 1 { d += cp[j] * s[i - j]; } if d == MInt::new(0) { m += 1; continue; } if 2 * l > i { // cp -= d/b * x^m * bp let factor = d * b.inv(); for j in 0..n + 1 - m { cp[m + j] -= factor * bp[j]; } m += 1; continue; } let factor = d * b.inv(); let tp = cp.clone(); for j in 0..n + 1 - m { cp[m + j] -= factor * bp[j]; } bp = tp; b = d; l = i + 1 - l; m = 1; } cp[0..l + 1].to_vec() } fn polymul(a: &[MInt], b: &[MInt], mo: &[MInt]) -> Vec { let n = a.len(); debug_assert_eq!(b.len(), n); debug_assert_eq!(mo.len(), n + 1); debug_assert_eq!(mo[n], 1.into()); let mut ret = vec![MInt::new(0); 2 * n - 1]; for i in 0..n { for j in 0..n { ret[i + j] += a[i] * b[j]; } } for i in (n..2 * n - 1).rev() { let val = ret[i]; for j in 0..n { ret[i - n + j] -= val * mo[j]; } } ret[..n].to_vec() } fn polypow(a: &[MInt], mut e: i64, mo: &[MInt]) -> Vec { let n = a.len(); debug_assert_eq!(mo.len(), n + 1); let mut prod = vec![MInt::new(0); n]; prod[0] += 1; let mut cur = a.to_vec(); while e > 0 { if e % 2 == 1 { prod = polymul(&prod, &cur, mo); } cur = polymul(&cur, &cur, mo); e /= 2; } prod } // Finds u a^e v^T by using Berlekamp-massey algorithm. // The linear map a is given as a closure. // Complexity: O(n^2 log e + nT(n)) where n = |u| and T(n) = complexity of a. // Ref: https://yukicoder.me/wiki/black_box_linear_algebra fn eval_matpow Vec>(mut a: F, e: i64, u: &[MInt], v: &[MInt]) -> MInt { let k = u.len(); // Find first 2k terms let mut terms = vec![MInt::new(0); 2 * k]; let mut cur = u.to_vec(); for pos in 0..2 * k { for i in 0..k { terms[pos] += cur[i] * v[i]; } cur = a(&cur); } let mut poly = berlekamp_massey(k, &terms); poly.reverse(); if poly.len() == 2 { let r = -poly[0]; return terms[0] * r.pow(e); } let mut base = vec![MInt::new(0); poly.len() - 1]; base[1] += 1; let powpoly = polypow(&base, e, &poly); let mut ans = MInt::new(0); for i in 0..poly.len() - 1 { ans += powpoly[i] * terms[i]; } ans } // https://yukicoder.me/problems/no/2156 (3) // 「「い」を少なくとも一文字含む。」という条件を外すと 1 通り多くなる。 // このとき fib(N) 通りである。 fn main() { let n: i64 = get(); println!("{}", eval_matpow(|x: &[MInt]| vec![x[1], x[0] + x[1]], n, &[1.into(), 0.into()], &[1.into(), 1.into()]) - 1); }