Two iron bars of the same length, one is sawn into three sections according to the ratio of 3:4:5, and the other is sawn into three sections according to the ratio of 7:9:11, how many different lengths can the sawn iron bars have?
两个同样长的铁条，一个按3：4：5的比例锯成三段，另一根按7：9：11的比例锯成三段，锯得的铁条有多少种不同的长度．
<result>5</result>