def main():
    N = int(input())
    a = list(map(int, input().split()))

    i = 0
    b = []
    ans = 0
    while i < N:
        if a[i] == 0 or a[i] == 1:
            ans = eval(str(ans) + '+' + str(a[i]))
        elif a[i] < 0:
            ans = eval(str(ans) + '-' + str(a[i]))
        else:
            ans = eval(str(ans) + '*' + str(a[i]))
        i += 1
    print(ans)

main()