Captain America is hiding from Thanos in a maze full of N rooms connected by M gates.
The maze is designed in such a way that each room leads to another room via gates. All connecting gates are unidirectional. Captain America is hiding only in those rooms which are accessible directly/indirectly through every other room in the maze.
Help Thanos find the number of rooms in which Captain America can hide.

Example 1:
Input:
N = 5 and M = 5
V = [[1, 2], [2, 3], [3, 4], [4, 3], [5, 4]]
Output: 2
Explanation:
We can look closesly after forming graph
than captain america only can hide in a
room 3 and 4 because they are the only room
which have gates through them. So,
answer is 2.
Example 2:
Input:
N = 2, M = 1
V = [[1, 2]]
Output: 1
Your Task:
You don't need to read input or print anything. Your task is to complete the function captainAmerica() which takes the integer N, an integer M and 2-d array V as input parameters and returns the Total no of rooms.
Expected Time Complexity: O(N+M)
Expected Auxiliary Space: O(N+M)

Constraints:
1 ≤ n ≤ 30000
1 ≤ m ≤ 200000
1 ≤ p,q ≤ n

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