Suppose 301*302*...*2014*2015=M, then how many consecutive zeros are there at the end of M?
设301*302*…*2014*2015=M，那么M的结尾有多少个连续的零．
<gadget id="calculator">1_715 / 5</gadget>
<output>343</output>

<gadget id="calculator">343 + 68 + 13</gadget>
<output>424</output>

<result>424</result>