T='helloworld'
def solve(N,S):
    ans=[]
    for i in range(N-10,-1,-1):
        for j in range(10):
        	if S[i+j]!='?' and S[i+j]!=T[j]: break
        else:
            res=[]
            for j in range(N):
                if i<=j<i+10:
                    res.append(T[j-i])
                elif S[j]=='?':
                    res.append('a')
                else:
                    res.append(S[j])
            ans.append(''.join(res))
    if not ans:
    	return '-1'
    return sorted(ans)[0]

t=int(input())
ans=[]
for _ in range(t):
    N=int(input())
    S=input()
    ans.append(solve(N,S))

print(*ans,sep='\n')