There are 38 students from Class 2 of Grade 4 participating in this year's "World Olympic Games Summer League" mathematics competition. There are 25 boys in this class. Then, how many more girls in this class participated in this year's "World Olympic Games Summer League" than the boys who did not participate in the competition.
四年级2班有38人参加今年的"世奥赛夏季联赛"数学竞赛，这个班有男生25人．那么，该班参加今年"世奥赛夏季联赛"的女生比没有参加比赛的男生多多少人．
<result>13</result>