PROBLEM STATEMENT
Your task is to find the length of the longest sequence of real numbers that satisfies some 
conditions.


You are given a vector <int> C. Each element of C corresponds to one condition.

If C[i] is negative, the condition is:
"The sum of every consecutive -C[i] terms must be negative."

If C[i] is positive, the condition is:
"The sum of every consecutive C[i] terms must be positive."


You should return the maximal length of a sequence that satisfies all the conditions.
If there exists an infinitely long sequence that satisfies all the conditions, return -1.

DEFINITION
Class:LongestSequence
Method:maxLength
Parameters:vector <int>
Returns:int
Method signature:int maxLength(vector <int> C)


CONSTRAINTS
-C will contain between 1 and 50 elements, inclusive.
-Each element in C will be between -1,000 and 1,000, inclusive.
-All elements in C will be pairwise distinct.
-No element in C will be 0.


EXAMPLES

0)
{-2,3}

Returns: 3

The sequence {2, -3, 2} satisfies all the conditions and its length is 3.

It can be proved that there is no valid sequence with more terms.

1)
{524}

Returns: -1

Any infinite sequence in which all elements are positive satisfies all the conditions.

2)
{1, -1}

Returns: 0

No sequence with positive length can satisfy both conditions.

3)
{11,-7}

Returns: 16



4)
{-227,690,590,-524}

Returns: 713



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