The director of your college is planning to send 2 people to the ICPC regionals. He wants them to be from different branches. You will be given a list of pairs of student ids. Each pair is made of students from the same branch. Determine how many pairs of students from different branches they can choose from.
Example 1:
Input:
N=5
P=3
pairs[]={{0,1},
{2,3},
{0,4}}
Output:
6
Explanation:
Their are total five studets 0,1,2,3,4.
Students [0,1,4] are from same bracnh while
[2,3] are from a different one.So we can choose
different pairs like: [0,2],[0,3],[1,2],[1,3],
[4,2],[4,3]

Example 2:
Input:
N=4
P=1
pairs[]={{0,2}}
Output:
5
Explanation:
[0,1],[0,3],[2,1],[2,3] and [1,3] are all possible
pairs because [0,2],[1] and [3] all belongs to
different branches.

Your Task:
You don't need to read input or print anything. Your task is to complete the function numberOfPairs() which takes the 2d array pairs[], its size P and an integer N representing total number of students as input parameters and returns the total number of pairs(as explianed in the question)..

Expected Time Complexity: O(N)
Expected Auxiliary Space: O(N)

Constraint:
1<=N<=10^{5}
1<=P<=10^{4}
0<=P[i][0],P[i][1]

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