Multiply the natural numbers starting from 1, that is, 1*2*3*4*5*... If there are 20 consecutive 0s at the end of the product, how much must be multiplied at least.
把自然数从1开始连乘，即1*2*3*4*5*…要使乘积的末尾有20个连续的0，则最少要乘到多少．
<result>95</result>