import copy

N=int(input())
K=[int(i) for i in input().split()]
ans=[]
def isWinning(state,depth):
    nextStates=[]
    now=state
    global ans
    #手の選択
    for i in range(N):
        if now[i]==False:
            continue
        for j in range(i+1,N):
            #a>b and b<c
            if K[i]>K[j] and now[j]==True:
                for m in range(j+1,N):
                    if K[j]<K[m] and now[m]==True:
                        nextK=copy.deepcopy(now)
                        nextK[i]=False
                        nextK[j]=False
                        nextK[m]=False
                        nextStates.append(nextK)
            #a<b and b>c
            if K[i]<K[j] and now[j]==True:
                for m in range(j+1,N):
                    if K[j]>K[m] and now[m]==True:
                        nextK=copy.deepcopy(now)
                        nextK[i]=False
                        nextK[j]=False
                        nextK[m]=False
                        nextStates.append(nextK)
    # print('now',now)
    # print('next',nextStates)
    for nextState in nextStates:
        if not isWinning(nextState,depth+1):
            if depth==0:
                # ans.append(copy.deepcopy(nextState))
                ans=copy.deepcopy(nextState)
                # print(ans)
            return True
    return False

start=[True for i in range(N)]
ret=isWinning(start,0)
# print(ret)
syote=[]
for i in range(len(ans)):
    if ans[i]==False:
        syote.append(i)
syote_string=' '.join(map(str,syote))
out=syote_string if ret==True else -1
print(out)