There is a line segment with a length of 2.1 meters. For the first time, divide the line segment into three equal parts and remove the middle part; for the second time, divide each of the remaining two line segments into five equal parts and remove the middle part; for the third time, remove all the remaining line segments After dividing each section into seven equal parts, remove the middle part, and then divide all the remaining line segments into nine equal parts, eleven equal parts, ..., continue this process, at least how many times in a row, before making the length of all the remaining line segments The sum is less than 0.8 meters.
有一条长2.1米的线段．第一次把这条线段三等分后去掉中间一部分，第二次再把剩下的两样线段中的每一段五等分后都去掉中间一部分，第三次再把剩下的所有条线段中的每一段七等分后都去掉中间一部分，以后将剩下的所有线段九等分，十一等分，…，继续这样的过程，至少连续多少次后，才使剩下的所有线段的长度的和小于0.8米．
<result>5</result>