package main

import . "fmt"
import . "strings"
import . "sort"
import "math/rand"

func main() {
	var t int
	Scan(&t)
	for ; t > 0; t-- {
		var n int
		var s string
		Scan(&n,&s)
		Println(solve(n, s))
	}
}

const H = "helloworld"
var bh = []byte(H)

func solve(n int, s string) string {
	if Contains(s, H) {
		return ReplaceAll(s, "?", "a")
	}
	b := []byte(s)
	ans := []string{}
	for i := len(b)-len(bh); i >= 0; i-- {
		ok := true
		for j, ch := range bh {
			if b[i+j] != '?' && b[i+j] != ch {
				ok = false
				break
			}
		}
		// コーナーケース
		// h??????????
		// WA hhelloworld
		// AC helloworlda
		if i > 0 && b[i-1] == 'h' && Count(string(b[i:i+len(bh)]), "?") == len(bh) {
			ok = false
		}
		if ok {
			x := []byte(s)
			for j, ch := range bh {
				x[i+j] = ch
			}
			ans = append(ans, ReplaceAll(string(x), "?", "a"))
			break
		}
	}
	if len(ans) > 0 {
		tmp := ans[0]
		Strings(ans)
		if tmp != ans[0] {
			println(tmp)
			println(ans[0])
			panic("bug")
		}
		return ans[0]
	}
	return "-1"
}

func init() {
	// check()
}

func check() {
	for t := 0; t < 1000; t++ {
		n := rand.Intn(40)+30
		b := make([]byte, n)
		for i := range b {
			c := rand.Intn(120)
			if c < 26 {
				b[i] = byte(c + 'a')
			} else {
				b[i] = '?'
			}
		}
		s := string(b)
		solve(n, s)
	}
}