There are two iron wires, one is 15 meters long and the other is 18 meters long. Cut them into small sections of the same length without any surplus. How many meters is the longest of each section?
有两根铁丝，一根长15米，一根长18米，把它们截成同样长的小段，不许有剩余，每段最长有几米？
<result>3</result>