mod = 998244353


def main():
    import sys
    input = sys.stdin.readline

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

        A = []
        for i in range(N - 10 + 1):
            T = []
            ok = 1
            for j in range(N):
                if i <= j <= i + 9:
                    if S[j] == "?":
                        T.append(H[j - i])
                    else:
                        if S[j] != H[j - i]:
                            ok = 0
                            break
                        else:
                            T.append(S[j])
                else:
                    if S[j] == "?":
                        T.append("a")
                    else:
                        T.append(S[j])
            if not ok:
                continue
            A.append("".join(T))
        if A:
            A.sort()
            print(A[0])
        else:
            print(-1)


if __name__ == '__main__':
    main()