N=int(input())
A=list(map(int,input().split()))
mod=998244353
start=pow(2,N-1,mod)
sa=start*pow(2,mod-2,mod)
ANS=0

p=start
for i in range(N):
    ANS=ANS+p*A[i]
    ANS%=mod
    p+=sa

print(ANS)