#define MD 998244353
ll@K,@L--,@R;
L>?=0;
Matrix<Mint>A(K+4,K+4);
Mint B[K+4];
rep(i,K+1){
A[i][0]=A[i][i]=1;
rep(j,1,i)A[i][j]=A[i-1][j]+A[i-1][j-1];
}
A[K+1][K+1]=A[K+2][K+2]=A[K+3][K+1]=K;
A[K+1][K]=A[K+1][K+2]=A[K+3][K+3]=A[K+3][K]=A[K+3][K+2]=B[0]=B[K+1]=B[K+2]=B[K+3]=1;
auto C=A**R;
if(L)C-=A**L;
Mint ans=0;
rep(i,K+4)ans+=C[K+3][i]*B[i];
wt(ans);