n = int(raw_input())
A = map(int, raw_input().split())
B = []
for k in range(len(A)):
    for i in range(len(A) - k):
        j = i+k
        B.append(max(A[i:j+1]))
A = B
B = []
for k in range(len(A)):
    for i in range(len(A) - k):
        j = i+k
        B.append(max(A[i:j+1]))
print sum(B)