def loi_muc_tieu(thao_tac):
    cache = False
    for ten in thao_tac:
        if ten == "bat_cache":
            cache = True
        if ten == "don_cache":
            cache = False
        if ten == "nhap_lai" and cache:
            return True
    return False

def thu_nho(du_lieu):
    assert loi_muc_tieu(du_lieu)
    while True:
        for i in range(len(du_lieu)):
            ung_vien = du_lieu[:i] + du_lieu[i + 1:]
            if loi_muc_tieu(ung_vien):
                du_lieu = ung_vien
                break
        else:
            return du_lieu

ket_qua = thu_nho(["mo", "bat_cache", "cuon", "nhap_lai", "dong"])
assert ket_qua == ["bat_cache", "nhap_lai"]
assert all(not loi_muc_tieu(ket_qua[:i] + ket_qua[i+1:]) for i in range(len(ket_qua)))
print(ket_qua)