Suppose M=1*4*7*10*...*1999, what is the number of consecutive zeros at the end of M?
设M=1*4*7*10*…*1999，则M的末尾连续0的个数为多少．
<gadget id="calculator">5 + 4 + 5 + 2 + 5 + 4 + 5 + 4 + 5 + 2 + 6 + 2 + 5 + 4 + 6 + 2 + 6 + 2 + 5 + 5 + 5 + 2 + 6 + 2 + 5 + 4 + 5 + 4 + 5 + 4 + 5 + 2 + 6 + 2 + 6 + 2 + 5 + 4 + 5 + 2</gadget>
<output>165</output>

<result>165</result>