At the time of the Kickstarter campaign, Barnett was a tenured professor at the University of Colorado, Boulder, making around $70,000 a year. Walking away was a slow, painful decision.
1. 找出最大值max和最小值min
，这一点在whatsapp中也有详细论述
Safe, private, and easy transactions
該公司並指出，用戶還可以採取其他額外措施來提升帳戶安全，包括封鎖陌生號碼的訊息或通話。