There is a number between 700 and 800 that cannot be divided by 15, 18 and 24. If the number is subtracted by 1, it will be divisible by 15, 18 and 24 at the same time. What is this number?
有一个数在700～800之间，用15、18和24去除都不能整除，如果把这个数减1，那么就能同时被15、18和24整除，这个数是多少．
<gadget id="calculator">720 + 1</gadget>
<output>721</output>

<result>721</result>