There are two ropes, the lengths of which are 28 meters and 35 meters respectively. If they are to be cut into small pieces of the same length, there will be no surplus. What is the longest length of each piece of rope?
有两根绳子，长度分别是28米和35米，要把它们截成同样长的小段，没有剩余，每段绳子最长是几米？
<result>7</result>