from sys import stdin
input = stdin.readline

H = "helloworld"

def func(idx):
    T = S[:]
    for i in range(10):
        if T[idx+i] != "?" and T[idx+i] != H[i]:
            return None
    for i in range(10):
        T[idx+i] = H[i]
    for i in range(N):
        if T[i] == "?":
            T[i] = "a"
    return "".join(T)

for _ in range(int(input())):
    N = int(input())
    S = list(input().rstrip("\n"))

    flag = False
    for i in reversed(range(N-9)):
        if S[i:i+10] == list(H):
            flag = True
            for j in range(N):
                if S[j] == "?":
                    S[j] = "a"
            break
    if flag:
        print("".join(S))
        continue

    idx = -1
    for i in reversed(range(N-9)):
        for j in range(10):
            if S[i+j] != "?" and S[i+j] != H[j]:
                break
        else:
            idx = i
            break
    else:
        print(-1)
        continue

    ans = []
    for i in reversed(range(max(idx-20, 0), idx+1)):
        res = func(i)
        if res is not None:
            ans.append(res)

    print(min(ans))