n = int(input()) a = list(map(int, input().split())) g = [0] * n g[0] = a[0] for i in range(1, n): g[i] = a[i] for j in range(i): if a[j] < a[i] and a[i] + g[j] > g[i]: g[i] = a[i] + g[j] print(max(g))