import sys

input = sys.stdin.readline
hoge = list("helloworld")
t = int(input())
for _ in range(t):
    n = int(input())
    s = list(input())
    if n < 10:
        print(-1)
        continue
    ans = -1
    for start in range(n - 10):
        okflag = 1
        for i in range(10):
            if s[start + i] == hoge[i] or s[start + i] == "?":
                continue
            else:
                okflag = 0
                break
        if okflag:
            ans = start

    if ans == -1:
        print(ans)
        continue
    for i in range(10):
        s[ans + i] = hoge[i]
    for i in range(n):
        if s[i] == "?":
            s[i] = "a"
    print("".join(s))
    # exit()