import sys

input = sys.stdin.readline
hoge = list("helloworld")
t = int(input())
for _ in range(t):
    n = int(input())
    s = list(input().rstrip())
    for i in range(n):
        if s[i] == "?":
            s[i] = "`"
    ans = -1
    kouho = []
    for start in range(n - 9):
        okflag = 1
        for i in range(10):
            if s[start + i] == hoge[i] or s[start + i] == "`":
                continue
            else:
                okflag = 0
                break
        if okflag:
            temp = s[:]
            for i in range(10):
                temp[i + start] = hoge[i]
                kouho.append(temp)
    if not kouho:
        print(ans)
        continue
    kouho.sort()
    ans = kouho[0]
    for i in range(n):
        if ans[i] == "`":
            ans[i] = "a"
    print("".join(ans))
    # exit()