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

INF = 10**18
DP = [[[-INF, INF] for _ in range(4)] for _ in range(n + 1)]
for i in range(4):
    DP[0][i][0] = DP[0][i][1] = 0
for i in range(n):
    a = A[i]
    for j in range(4):
        for k in range(2):
            if DP[i][j][k] == -INF or DP[i][j][k] == INF:
                continue
            DP[i + 1][0][0] = max(DP[i + 1][0][0], DP[i][j][k] + a)
            DP[i + 1][0][1] = min(DP[i + 1][0][1], DP[i][j][k] + a)
            DP[i + 1][1][0] = max(DP[i + 1][1][0], DP[i][j][k] - a)
            DP[i + 1][1][1] = min(DP[i + 1][1][1], DP[i][j][k] - a)
            DP[i + 1][2][0] = max(DP[i + 1][2][0], DP[i][j][k] * a)
            DP[i + 1][2][1] = min(DP[i + 1][2][1], DP[i][j][k] * a)
            if a != 0:
                DP[i + 1][3][0] = max(DP[i + 1][3][0], DP[i][j][k] // a)
                DP[i + 1][3][1] = min(DP[i + 1][3][1], DP[i][j][k] // a)
ans = -INF
for i in range(4):
    ans = max(ans, DP[n][i][0])
print(ans)