Fibonacci sequence#2019
A set of distinct integers is given. Find the length of the longest sequence of Fibonacci numbers that can be arranged from them. Each number can be used in the sequence no more than once. The sequence is called the Fibonacci sequence, if
F_1 =
F_2 =
F_i = F_{i-2} + F_{i-1}
The first line contains the number (2 \leq n \leq 10000) of elements in the set. The second line contains distinct integers a_i (1 \leq a_i \leq 10^9).
Print the length of the longest Fibonacci sequence, that can be created from given numbers.
Example 1