0 abbreviation for highest common factor: the highest number that a set of two or more different numbers can be divided by exactly -- 最大公约数(highest common factor的缩写)
We can complete it step by step however long the road is and it can't be completed however short the road is if you don't even mark your footprint.
再长的路,一步步也能走完,再短的路,不迈开双脚也无法到达。