T = int(input())
def dist(i):
    a = S[i:i+10]
    b = "helloworld"
    cnt = 0
    for k in range(10):
        if a[k]=="?" or a[k]==b[k]:
            continue
        cnt += 1
    return cnt
for _ in range(T):
    N = int(input())
    S = list(input())
    A = []
    for i in range(N-10,-1,-1):
        d = dist(i)
        if d==0:
            A.append(i)
    if len(A)==0:
        print(-1)
    else:
        B = []
        for i in A:
            T = S[:]
            T[i:i+10] = list("helloworld")
            for j in range(N):
                if T[j]=="?":
                    T[j] = "a"
            B.append("".join(T))
        B = sorted(B)
        print(B[0])