import os
import sys
from io import BytesIO, IOBase

BUFSIZE = 8192


class FastIO(IOBase):
	newlines = 0
	
	def __init__(self, file):
		self._fd = file.fileno()
		self.buffer = BytesIO()
		self.writable = "x" in file.mode or "r" not in file.mode
		self.write = self.buffer.write if self.writable else None
	
	def read(self):
		while True:
			b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
			if not b:
				break
			ptr = self.buffer.tell()
			self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
		self.newlines = 0
		return self.buffer.read()
	
	def readline(self):
		while self.newlines == 0:
			b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
			self.newlines = b.count(b"\n")+(not b)
			ptr = self.buffer.tell()
			self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
		self.newlines -= 1
		return self.buffer.readline()
	
	def flush(self):
		if self.writable:
			os.write(self._fd, self.buffer.getvalue())
			self.buffer.truncate(0), self.buffer.seek(0)


class IOWrapper(IOBase):
	def __init__(self, file):
		self.buffer = FastIO(file)
		self.flush = self.buffer.flush
		self.writable = self.buffer.writable
		self.write = lambda s:self.buffer.write(s.encode("ascii"))
		self.read = lambda:self.buffer.read().decode("ascii")
		self.readline = lambda:self.buffer.readline().decode("ascii")


sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
input = lambda:sys.stdin.readline().rstrip("\r\n")


targ = "helloworld"

T = int(input())
for _ in range(T):
	n = int(input())
	s = list(input())
	can = 0
	canlist = []
	for i in range(n-9):
		mode = 1
		for j in range(10):
			if s[i+j] != "?" and s[i+j] != targ[j]:
				mode = 0
		if mode:
			can = 1
			canlist.append(i)
	if can == 0:
		print(-1)
		continue
	v = s[::]
	for i in range(n):
		if v[i] == "?":
			v[i] = "a" 
	i = canlist[-1]
	w = v[::]
	for j in range(10):
		w[i+j] = targ[j]
	print("".join(w))