There is a column of numbers, the first and second numbers are represented by letters A and B respectively, and then continue to write numbers, the third number is the sum of the first and second numbers, and the fourth number is the second and second numbers The sum of the three numbers...write down in turn, when the eight numbers are written, it is exactly equal to 47, knowing that A=1, what number is represented by the letter B?
有一列数，第一和第二两个数分别用字母A、B来表示，接着继续写数，第三个数为第一和第二个数的和，第四个数为第二和第三个数的和…依次写下去，当写到八个数时，正好等于47，已知A=1，字母B表示的数是多少？
<gadget id="calculator">47 - 8</gadget>
<output>39</output>

<gadget id="calculator">39 / 13</gadget>
<output>3</output>

<result>3</result>