T = int(input())
U = "helloworld"

for _ in range(T):
    N = int(input())
    S = input()

    l = []
    for i in  range(N - 10 + 1):
        flag = True
        for j in range(10):
            if S[i + j] == "?" or S[i + j] == U[j]:
                pass
            else:
                flag = False
                break
        if flag:
            l.append(i)
    while len(l) > 1:
        i = l.pop()
        j = l.pop()
        flag = True
        for k in range(N):
            if i <= k <= i + 9:
                c = U[k - i]
            else:
                if S[k] == "?":
                    c = "a"
                else:
                    c = S[k]
            if j <= k <= j + 9:
                d = U[k-j]
            else:
                if S[k] == "?":
                    d = "a"
                else:
                    d = S[k]
            if c < d:
                l.append(i)
                flag = False
                break
            elif c > d:
                l.append(j)
                flag = False
                break
        if flag:
            l.append(i)
    if len(l) == 0:
        print(-1)
        continue
    i = l[0]
    ans = []
    for k in range(N):
        if i <= k <= i + 9:
            ans.append(U[k-i])
        else:
            if S[k] == "?":
                ans.append("a")
            else:
                ans.append(S[k])
    print("".join(ans))