#include #include using namespace std; typedef long long ll; typedef vector vec; typedef vector mat; ll mod = 998244353; mat mul(const mat &A, const mat &B){ mat C(A.size(), vec(B[0].size())); for(int i = 0; i < A.size(); i++){ for(int k = 0; k < B.size(); k++){ for(int j = 0; j < B[0].size(); j++){ C[i][j] = (C[i][j] + A[i][k] * B[k][j]) % mod; } } } return C; } mat pow(mat A, ll n){ mat B(A.size(), vec(A.size())); for(int i = 0; i < A.size(); i++){ B[i][i] = 1ll; } while(n > 0){ if(n & 1) B = mul(B, A); A = mul(A, A); n >>= 1; } return B; } int main(){ int n, k; cin >> n >> k; int siz = k*k*k; mat A(siz, vec(siz, 0)), B(siz, vec(1,0)); B[0][0] = 1; for(int i = 0; i < siz; i++){ int x[3], cp = i; for(int j = 2; j >= 0; j--){ x[j] = cp%k; cp /= k; } x[2] = (x[2]+1)%k; A[x[0]*k*k + x[1]*k + x[2]][i]++; x[2] = (x[2]-1+k)%k; for(int j = 1; j >= 0; j--){ (x[j] += x[j+1]) %= k; A[x[0]*k*k + x[1]*k + x[2]][i]++; (x[j] += k-x[j+1]) %= k; } } mat C = mul(pow(A, n), B); ll ans = 0; for(int i = 0; i < k*k; i++){ (ans += C[i][0]) %= mod; } cout << ans << endl; return 0; }