chōngyàotiáojiàn
ㄔㄨㄥ ㄧㄠˋ ㄊㄧㄠˊ ㄐㄧㄢˋ
Simplified 充要条件
Taivo → Settings → Partner inbox → Make the link. It stays in this browser.
Keep 充要條件 and it comes back until you know it.