Count Unique Coordinate Spots

You are given a list of coordinate pairs in the 2D plane. Each coordinate is described by two integers representing the X and Y positions. Your task is to determine the number of unique coordinate pairs.

Formally, if the list of coordinates is given by \(\{(x_i, y_i)\}_{i=1}^n\), you need to compute the size of the set:

[ S = {(x_i,y_i);:;1 \le i \le n} ]

For example, for the coordinate list:

8
1 2
2 3
1 2
4 5
4 5
6 7
8 9
6 7

the answer is 5 since there are 5 unique coordinate pairs.

inputFormat

The input is read from stdin and has the following format:

1. An integer n which indicates the number of coordinate pairs.
2. n lines follow, each line containing two space-separated integers representing the coordinates x and y.

\(1 \leq n \leq 10^5\) and the coordinate values are integers.

outputFormat

Output the number of unique coordinate pairs to stdout.

The result is a single integer representing the count of distinct points.

## sample

8
1 2
2 3
1 2
4 5
4 5
6 7
8 9
6 7

5