T = int(input())
def dist(i):
    a = S[i:i+10]
    b = "helloworld"
    cnt = 0
    for k in range(10):
        if a[k]=="?" or a[k]==b[k]:
            continue
        cnt += 1
    return cnt
for _ in range(T):
    N = int(input())
    S = list(input())
    flag = 0
    for i in range(N-10,-1,-1):
        d = dist(i)
        if d==0:
            S[i:i+10] = list("helloworld")
            flag = 1
            break
    if flag==0:
        print(-1)
    else:
        for i in range(N):
            if S[i]=="?":
                S[i] = "a"
        print("".join(S))