import sys

sys.setrecursionlimit(10**7)
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int,sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LI2(): return list(map(int,sys.stdin.readline().rstrip()))
def S(): return sys.stdin.readline().rstrip()
def LS(): return list(sys.stdin.readline().rstrip().split())
def LS2(): return list(sys.stdin.readline().rstrip())


N = I()
A = [0]+LI()
mod = 998244353

if N == 1:
    print(A[0])
    exit()

ans = 0
for i in range(1,N+1):
    ans += (i+1)*A[i]
    ans %= mod

ans *= pow(2,N-2,mod)
ans %= mod
print(ans)