Zhang Qiang and his wife attended a party, and there were 4 other couples present at the same time. When they met, they shook hands with each other. Of course, couples did not shake hands, and no one shook hands with the same person twice. The number of handshakes of 9 people including his wife is found to be different. How many times did Zhang Qiang's wife shake hands?
张强夫妇参加了一次聚会，同时出席的还有另外4对夫妇，一见面时大家互相握手，当然夫妇之间不握手，也没有人与同一个人握2次手，握手完毕后，张强统计了包括妻子在内9个人握手的次数，发现握手的次数互不相同，请问张强的妻子握了多少次手．
<result>4</result>