import sys # sys.setrecursionlimit(1000005) int1 = lambda x: int(x)-1 pDB = lambda *x: print(*x, end="\n", file=sys.stderr) p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr) def II(): return int(sys.stdin.readline()) def LI(): return list(map(int, sys.stdin.readline().split())) def LLI(rows_number): return [LI() for _ in range(rows_number)] def LI1(): return list(map(int1, sys.stdin.readline().split())) def LLI1(rows_number): return [LI1() for _ in range(rows_number)] def SI(): return sys.stdin.readline().rstrip() # dij = [(0, 1), (-1, 0), (0, -1), (1, 0)] # dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)] inf = (1 << 63)-1 # inf = (1 << 31)-1 md = 10**9+7 # md = 998244353 n = II() aa = LI() m=1 ans=0 for i,a in enumerate(aa): m*=a m%=md if i==n-1:break ans+=m*pow(3,n-i-2,md)*2%md ans%=md ans+=m print(ans%md)