CF365B.The Fibonacci Segment

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题目描述

You have array $a_{1},a_{2},...,a_{n}$ . Segment $[l,r]$ ( $1<=l<=r<=n$ ) is good if $a_{i}=a_{i-1}+a_{i-2}$ , for all $i$ $(l+2<=i<=r)$ .

Let's define $len([l,r])=r-l+1$ , $len([l,r])$ is the length of the segment $[l,r]$ . Segment $[l_{1},r_{1}]$ , is longer than segment $[l_{2},r_{2}]$ , if len([l_{1},r_{1}])>len([l_{2},r_{2}]) .

Your task is to find a good segment of the maximum length in array $a$ . Note that a segment of length $1$ or $2$ is always good.

输入格式

The first line contains a single integer $n$ ( $1<=n<=10^{5}$ ) — the number of elements in the array. The second line contains integers: $a_{1},a_{2},...,a_{n}$ ( $0<=a_{i}<=10^{9}$ ).

输出格式

Print the length of the longest good segment in array $a$ .

输入输出样例

输入#1
```
10
1 2 3 5 8 13 21 34 55 89
```
输出#1
```
10
```
输入#2
```
5
1 1 1 1 1
```
输出#2
```
2
```

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