When a natural number is divided by 2, the remainder is 1. After adding 1 to this number, the remainder is 2 when divided by 3. This number is exactly divisible by subtracting 1 and dividing by 5. What is the smallest natural number?
一个自然数除以2余1，这个数加1后，除以3余2，这个数减去1除以5刚好整除，这个自然数最小是多少．
<gadget id="calculator">2 * 3 * 5</gadget>
<output>30</output>

<gadget id="calculator">30 + 1</gadget>
<output>31</output>

<result>31</result>