from re import A


hello = "helloworld"

def solve():
    n = int(input())
    S = input()

    if hello in S:
        ans = []
        for s in S:
            if s == "?":
                s = "a"
            ans.append(s)

        return "".join(ans)


    for i in range(n-10,-1,-1):
        ok = 1
        for j in range(10):
            if S[i+j] != "?" and S[i+j] != hello[j]:
                ok = 0

        if ok == 0:
            continue
        S = list(S)
        for j in range(10):
            S[i+j] = hello[j]

        ans = []
        for s in S:
            if s == "?":
                s = "a"
            ans.append(s)

        return "".join(ans)

    return -1        

t = int(input())
for _ in range(t):
    print(solve())