#include <iostream>
#include <vector>

using i32 = int;
using u32 = unsigned;
using i64 = long long;
using u64 = unsigned long long;

template <i32 MOD>
struct Mint {
  i32 n;
  constexpr Mint(i32 n = 0): n(n) {}
  constexpr Mint operator-() const { return Mint(n ? MOD - n: 0); }
  constexpr Mint &operator+=(const Mint &rhs){ n += rhs.n; if(n >= MOD) n -= MOD; return *this; }
  constexpr Mint &operator-=(const Mint &rhs){ if(rhs.n > n) n += MOD; n -= rhs.n; return *this; }
  constexpr Mint &operator*=(const Mint &rhs){ n = (i64) n * rhs.n % MOD; return *this; }
  constexpr Mint inv() const {
    i32 x = MOD;
    i32 y = n;
    i32 b = 0, d = 1;
    while(y){
      i32 q = x / y;
      x = x % y;
      b -= q * d;
      std::swap(x, y);
      std::swap(b, d);
    }
    if(b < 0) b += MOD;
    return b;
  }
  constexpr Mint &operator/=(const Mint &rhs){ n = (i64) n * rhs.inv().n % MOD; return *this; }
  friend constexpr Mint operator+(const Mint &lhs, const Mint &rhs){ return Mint(lhs) += rhs; }
  friend constexpr Mint operator-(const Mint &lhs, const Mint &rhs){ return Mint(lhs) -= rhs; }
  friend constexpr Mint operator*(const Mint &lhs, const Mint &rhs){ return Mint(lhs) *= rhs; }
  friend constexpr Mint operator/(const Mint &lhs, const Mint &rhs){ return Mint(lhs) /= rhs; }
  friend constexpr bool operator==(const Mint &lhs, const Mint &rhs){ return lhs.n == rhs.n; }
  friend constexpr bool operator!=(const Mint &lhs, const Mint &rhs){ return lhs.n != rhs.n; }
  friend std::ostream &operator<<(std::ostream &os, const Mint &rhs){ return os << rhs.n; }
};

template <class T>
T modpow(T x, int n){
  T r(1);
  for(; n; n >>= 1){
    if(n&1) r *= x;
    x *= x;
  }
  return r;
}

constexpr u32 mod = 998244353;
using mint = Mint<mod>;

using poly = std::vector<mint>;

poly mult(const poly &lhs, const poly &rhs){
  poly r(lhs.size() + rhs.size() - 1);
  for(u32 i = 0; i < lhs.size(); i++){
    for(u32 j = 0; j < rhs.size(); j++){
      r[i+j] += lhs[i] * rhs[j];
    }
  }
  return r;
}

void printv(const poly a){
  for(u32 i = 0; i < a.size(); i++) std::cout << a[i] << ' ';
  std::cout << std::endl;
}

poly denom(u32 k, mint e1, mint e2){
  std::vector<mint> fib(k+2);
  fib[0] = 0;
  fib[1] = 1;
  for(u32 i = 2; i < fib.size(); i++) fib[i] = e1 * fib[i-1] - e2 * fib[i-2];
  poly den(k+2);
  den[0] = 1;
  mint c = 1;
  for(u32 i = 1; i < den.size(); i++, c *= e2) den[i] = -c * den[i-1] * fib[k+2-i] / fib[i];
  den = mult(den, { 1, mod-1 });
  return den;
}

int main(){
  u64 n;
  u32 k;
  std::cin >> n >> k;

  std::vector<mint> fib(k+2);
  fib[0] = 0;
  fib[1] = 1;
  for(u32 i = 2; i < fib.size(); i++) fib[i] = fib[i-1] + fib[i-2];

  poly den = denom(k, 1, mod-1);


  poly num(k+2);
  for(u32 i = 1; i < num.size(); i++) num[i] = num[i-1] + modpow(fib[i], k);

  num = mult(num, den);
  num.resize(k+2);

  mint e1 = 1;
  mint e2 = mod-1;

  for(;n; n>>=1){
    poly dem = den;
    for(u32 i = 1; i < dem.size(); i += 2) dem[i] = -dem[i];
    num = mult(num, dem);
    for(u32 i = n&1; i < num.size(); i += 2) num[i/2] = num[i];
    num.resize(num.size()/2);
    e1 = e1 * e1 - 2*e2;
    e2 = e2 * e2;
    den = denom(k, e1, e2);
  }

  std::cout << num[0] << std::endl;

  return 0;
}