import sys import copy def ring(H,n): if n==0: return H[1:] elif n==len(H): return H[:-2] else: for i in range(n): H.append(H[i]) for i in range(n+1): del(H[0]) return H def solve(G,i): #n=0或-1，取了之后删除节点 get_=G[i] del(G[i]) return G,get_ def input_(): #N=int(input()) N=int(sys.stdin.readline()) H=[] for i in range(N): H.append(int(sys.stdin.readline())) return H,N H,N=input_() #每个情况都试一遍 max_val=0 for i in range(N): ming=H[i] hong=0 G=copy.deepcopy(H) ring_=ring(G,i) ind=0 for j in range(N-1): #红拿环里第一个 if j%2==0: if int(ring_[0])>int(ring_[-1]): ring_,val=solve(ring_,0) hong=hong+int(val) else: ring_,val=solve(ring_,-1) hong = hong + int(val) else: if int(ring_[0])>int(ring_[-1]): ring_,val=solve(ring_,0) ming=ming+int(val) else: ring_,val=solve(ring_,-1) ming = ming + int(val) if abs(ming-hong)>max_val: max_val=abs(ming-hong) print(max_val)