HW = 'helloworld' for _ in range(int(input())): n = int(input()) s = input() for i in range(n - 10, -1, -1): for k in range(10): if s[i + k] != '?' and s[i + k] != HW[k]: break else: print(s[:i].replace('?', 'a') + HW + s[i + 10:].replace('?', 'a')) break else: print(-1)