Arrange 10 numbers in a row from left to right. Starting from the third number, each number is exactly equal to the sum of the two preceding numbers. It is known that the ninth and tenth numbers are 212 and 343 respectively. So what is the first number?
将10个数从左到右排成一行，从第三个数开始，每个数恰好等于它前面两个数的和，已知第9个数和第10个数分别是212和343．那么，第一个数是多少．
<gadget id="calculator">343 - 212</gadget>
<output>131</output>

<gadget id="calculator">212 - 131</gadget>
<output>81</output>

<gadget id="calculator">131 - 81</gadget>
<output>50</output>

<gadget id="calculator">81 - 50</gadget>
<output>31</output>

<gadget id="calculator">50 - 31</gadget>
<output>19</output>

<gadget id="calculator">31 - 19</gadget>
<output>12</output>

<gadget id="calculator">19 - 12</gadget>
<output>7</output>

<gadget id="calculator">12 - 7</gadget>
<output>5</output>

<result>5</result>