I,R=input,range
N=int(I())
A=list(map(int,I().split()))
P=998244353
Q=[1,1]
F=Q[:]
G=Q[:]
for i in R(2,2*N):
	Q+=[P-P//i*Q[P%i]%P]
	F+=[F[-1]*i%P]
	G+=[G[-1]*Q[i]%P]
print(sum(A[i]*F[2*N-2-i]*G[N-1-i]*(i+1)for i in R(N))*G[N-1]*Q[N]%P)