def substitutable(S,T):
    return all(S[i]==T[i] or S[i]=="?" or T[i]=="?" for i in range(len(S)))

def solve():
    N=int(input())
    S=input()

    H="helloworld"
    for i in range(N-len(H),-1,-1):
        if substitutable(S[i:i+len(H)],H):
            return S[:i].replace("?","a")+H+S[i+len(H):].replace("?","a")
    else:
        return -1

#==================================================
T=int(input())
print(*[solve() for t in range(T)], sep="\n")