Cut two colored ribbons of 20 cm and 16 cm into short colored ribbons of the same length and there is no surplus. What is the longest length of each short colored ribbon in centimeters?
把20厘米、16厘米的两根彩带剪成长度一样的短彩带且没有剩余，每根短彩带最长是多少厘米．
<result>4</result>