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In JOI village, there is a vast patch of unused land on which **N** scarecrows stand. Several times a year, the residents of JOI village hold a festival in the barren land, surrounded by the scarecrows. The village chief received a prophecy from the scarecrows and is obliged to build a field on the wastelands to facilitate the festival. In accordance to the prophecy, the village chief has declared that the field must satisfy these conditions:

- The boundaries of the field are straight lines parallel to the north-south direction or the east-west direction. The field is a rectangle.
- There are two scarecrows, one at the southwest corner and the other at the northeast corner.
- There are no other scarecrows within the field.

Of course, you are not allowed to move the precious scarecrows. Given the positions of the **N** scarecrows, how many ways can a field be built in accordance with the prophecy?

### Input

Read from standard input.

- On the first line, there is one integer
**N**. This means that there are**N**scarecrows in the wastelands. - On the ith line of the next
**N**lines, there are two integers,**X**and_{i}**Y**. This means that the ith scarecrow is at (_{i}**X**,_{i}**Y**) on the xy plane representing the wastelands. East is in the direction of the positive x-axis and north is in the direction of the positive y-axis._{i}

### Output

Print one line containing one integer to standard output, representing the number of ways the field can be built in accordance with the prophecy.

### Constraints

All test cases satisfy the following constraints:

- 1 ≤
**N**≤ 200 000. - 0 ≤
**X**≤ 1 000 000 000 (1 ≤ i ≤_{i}**N**). - 0 ≤
**Y**≤ 1 000 000 000 (1 ≤ i ≤_{i}**N**). **X**(1 ≤ i ≤_{i}**N**) are all mutually distinct.**Y**(1 ≤ i ≤_{i}**N**) are all mutually distinct.

### Subtasks

Subtask 1 (5 points):

**N**≤ 400 is satisfied.

Subtask 2 (10 points):

**N**≤ 5 000 is satisfied.

Subtask 3 (85 points):

No further constraints.

### Sample Input 1

```
4
0 0
2 2
3 4
4 3
```

### Sample Output 1

```
3
```

### Explanation

In this example, there are three ways to build a prophecy-fulfilling field.

- The rectangle with (0, 0) as the southwest corner and (2, 2) as the northeast corner.
- The rectangle with (2, 2) as the southwest corner and (3, 4) as the northeast corner.
- The rectangle with (2, 2) as the southwest corner and (4, 3) as the northeast corner.

### Sample Input 2

```
10
2 1
3 0
6 3
10 2
16 4
0 8
8 12
11 14
14 11
18 10
```

### Sample Output 2

```
15
```

### Explanation

In this example, the scarecrows' positions are as follows:

### Tags

### Subtasks and Limits

Subtask | Score | #TC | Time | Memory | Scoring |
---|---|---|---|---|---|

1 | 5 | 10 | 1.5s | 256MB | Minimum |

2 | 10 | 12 | 1.5s | 256MB | Minimum |

3 | 85 | 20 | 1.5s | 256MB | Minimum |

4 | 0 | 2 | 1.5s | 256MB | Minimum |

### Judge Compile Command

g++-8 ans.cpp -o scarecrows -Wall -Wshadow -static -O2 -lm -m64 -s -w -std=gnu++17 -fmax-errors=512