If a natural number is divided by 2, the remainder is 1, when divided by 3, the remainder is 2, when divided by 4, the remainder is 1, and when divided by 5, the remainder is 1. What is the minimum number of this number?
某个自然数除以2余1，除以3余2，除以4余1，除以5也余1，则这个数最小是多少．
<gadget id="calculator">20 * 2</gadget>
<output>40</output>

<gadget id="calculator">40 + 1</gadget>
<output>41</output>

<result>41</result>