from itertools import combinations
N = int(input())
A = list(map(int,input().split()))
B = list(range(N))
def dfs(i,v):
    global B
    for u in combinations(B,3):
        x = A[u[0]]
        y = A[u[1]]
        z = A[u[2]]
        if x!=y and y!=z and z!=x and (y==max(x,y,z) or y==min(x,y,z)):
            if len(B)-3<3:
                return i,u
            B.remove(u[0])
            B.remove(u[1])
            B.remove(u[2])
            i1,u1 = dfs(1-i,u)
            if i1==i:
                B += u
                B = sorted(B)
                return i,u
            B += u
            B = sorted(B)
        else:continue
    return 1-i,v
i,u = dfs(0,[])
if i==0:
    print(*u)
else:
    print(-1)