An array A consisting of N integers is given. A list is constructed from this array as follows

An array A consisting of N integers is given. A list is constructed from this array as follows:

    the first node (the head) is located at index 0;
    the value of a node located at index K is A[K];
    the successor of a node located at index K is located at index A[K];
    if the value of a node is −1 then it is the last node of the list.

For example, for array A such that:

A[0] = 1  A[1] = 4  A[2] = -1
A[3] = 3  A[4] = 2

the following list is constructed:

    the first node (the head) is located at index 0 and has a value of 1;
    the second node is located at index 1 and has a value of 4;
    the third node is located at index 4 and has a value of 2;
    the fourth node is located at index 2 and has a value of −1.

Write a function:

int solution(int A[], int N);

that, given a non-empty zero-indexed array A consisting of N integers, returns the length of the list constructed from A in the above manner.

Assume that:

    N is an integer within the range [1..200,000];
    each element of array A is an integer within the range [−1..200,000];
    it will always be possible to construct the list and its length will be finite.

For example, given array A such that:

A[0] = 1  A[1] = 4  A[2] = -1
A[3] = 3  A[4] = 2

the function should return 4, as explained in the example above.