一个软件牵出几个

运行下面这段程序，填写它打印出来的结果。

DEPS = {"甲": ["乙", "丙"], "乙": ["丁"], "丙": [], "丁": []}

def need(name, seen):
    for d in DEPS.get(name, []):
        if d not in seen:
            seen.append(d)
            need(d, seen)
    return seen

got = need("甲", [])
print(str(len(got)) + "/" + ",".join(got))