N=int(input())
A=list(map(int,input().split()))

mod=998244353

FACT=[1]
for i in range(1,5*10**5+1):
    FACT.append(FACT[-1]*i%mod)

FACT_INV=[pow(FACT[-1],mod-2,mod)]
for i in range(5*10**5,0,-1):
    FACT_INV.append(FACT_INV[-1]*i%mod)

FACT_INV.reverse()

def Combi(a,b):
    if 0<=b<=a:
        return FACT[a]*FACT_INV[b]%mod*FACT_INV[a-b]%mod
    else:
        return 0

def cat(i,j):
    return (Combi(i+j+1,j)-2*Combi(i+j,j-1))%mod

A.reverse()
ANS=0
for i in range(N):
    ANS+=A[i]*cat(N-1,i)
    ANS%=mod

print(ANS)