import sys

# sys.setrecursionlimit(200005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()

# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = (1 << 63)-1
# inf = (1 << 31)-1
# md = 10**9+7
md = 998244353

t = "helloworld"
def solve():
    def ok(si):
        if n-si < 10: return False
        for i, c in enumerate(t):
            if s[si+i] == "?": continue
            if s[si+i] != c: return False
        return True

    n = II()
    s = SI()

    if t in s:
        s = s.replace("?", "a")
        print(s)
        return

    ans = "z"*n
    for si in range(n)[::-1]:
        if ok(si):
            cur = s[:si]+t+s[si+10:]
            cur = cur.replace("?", "a")
            ans = min(ans, cur)
    if ans == "z"*n:
        print(-1)
    else:
        print(ans)

for _ in range(II()):
    solve()