for _ in range(int(input())):
    n = int(input())
    s = input()
    t = "helloworld"
    if t in s: print(s.replace("?","a")); continue
    for i in range(n-9):
        f = True
        for j in range(10):
            if "?"!=s[i+j]!=t[j]: f = False
        if f: print(s[:i].replace("?","a")+t+s[i+10:].replace("?","a")); break
    else: print(-1)