修改时长
https://ja.wikipedia.org/wiki/%E7%89%B9%E5%91%BD%E3%81%8A%E3%81%B0%E3%81%95%E3%82%93%E6%A4%9C%E4%BA%8B!_%E8%8A%B1%E6%9D%91%E7%B5%A2%E4%B9%83%E3%81%AE%E4%BA%8B%E4%BB%B6%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB