T=int(input())
for _ in range(T):
    N=int(input())
    S=input()
    ans=-1

    key="helloworld"
    if key in S:
    	print(S.replace("?","a"))
    else:
	    for i in range(N-9):
	        flag=True
	        for j in range(10):
	            if not (S[i+j]=="?" or S[i+j]==key[j]):
	                flag=False
	                break
	        if flag:
	            ans=max(ans,i)
	    if ans==-1:
	        print(-1)
	    else:
	        ans2=[a for a in S.replace("?","a")]
	        for j in range(10):
	            ans2[j+ans]=key[j]
	        print(*ans2,sep="")