plan B
contingency plan
system B
https://source.unsplash.com/featured/?plan-B#.png
/suto3/google.iconplan B
/suto3/Google画像検索.iconplan B
/suto3/Google定義検索.icon plan B
/suto3/wikipedia.iconplan B
/suto3/weblio.icon plan B
/suto3/kotobank.icon plan B
/suto3/jisho.icon plan B