T = int(input())

def check(s):
    s0 = "helloworld"
    for i in range(10):
        if s[i] == "?" or s[i] == s0[i]:
            continue
        else:
            return False
    return "True"

def solve():
    N = int(input())
    S = input()
    for i in reversed(range(N - 9)):
        if check(S[i:i + 10]):
            S = S[:i] + "helloworld" + S[i + 10:]
            print(S.replace("?", "a"))
            break
    else:
        print(-1)

for _ in range(T):
    solve()