There are a series of numbers lined up, the first number is the first number (A) in the answer to the previous question, the second number is the second number (B) in the answer to the previous question, starting from the third number , each number is exactly the sum of the previous two numbers. Then in this series of numbers, what is the remainder obtained when the 1991st number is divided by 3?
有一串数排成一行，其中第一个数是上题答案中的第一个数(A)，第二个数是上题答案中的第二个数(B)，从第三个数起，每个数恰好是前两个数的和．那么在这串数中，第1991个数被3除所得的余数是多少．
<result>2</result>