T = int(input())

n = [0] * T
s = [0] * T
for i in range(T):
	n[i] = int(input())
	s[i] = input()
	
u = "helloworld"
ans = [-1] * T
for i in range(T):
	N = n[i]
	S = list(s[i])
	
	for j in range(N-10, -1, -1):
		f = 1
		for k in range(10):
			if S[j+k] != u[k] and S[j+k] != "?":
				f = 0
				break
		if f == 1:
			#print(i, j, S[j:j+10])
			for k in range(10):
				S[j+k] = u[k]
			break
		
	#print(i, f, S)
	if f == 1:
		for j in range(N):
			if S[j] == "?":
				S[j] = "a"
		ans[i] = "".join(S)
		
for x in ans:
	print(x)