def isKDMT(X):
	return len(set(X))==3 and(min(X)==X[1] or max(X)==X[1])
N=input()
K=map(int,raw_input().split())
win=[]
def solve(k,l,d=0):
	global win
	for a in range(N):
		if k[a]==0:continue
		for b in range(a+1,N):
			if k[b]==0:continue
			for c in range(b+1,N):
				if k[c]==0:continue
				if isKDMT([k[a],k[b],k[c]]):
					n=k[:]
					n[a]=n[b]=n[c]=0
					r=solve(n,l-3,d+1)
					if r==False:
						if d==0:
							print a,b,c
						return True
	return False
if not solve(K,N):print -1