2. Even Fibonacci Numbers

Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with $1$$1$ and $2$$2$, the first $10$$10$ terms will be:

By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.

2. 偶斐波那契数

斐波那契数列中，每一项都是其前两项的和。若斐波那契数列的开始两项是 $1$$1$、$2$$2$，那么该数列的前十项为：

斐波那契数列中所有不超过四百万的项中，所有偶数的和是？

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