There are three iron wires, one is 12m long, the other is 15m long, and the other is 18m long. Cut them into small pieces of the same length.
有三根铁丝，一根长12m，一根长15m，另一根长18m，把它们截成同样长的小段，不可有剩余，每段最长有几米？
<result>3</result>