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))