Given n line segments on the number line. Choose the maximum number of line segments such that no two line segments share a common point.
### Input
- The first line contains two integers n.
- The next n lines each contain two integers l,r, representing a line segment extending from point l to r on the number line.
### Output
- Print an integer, the maximum number of line segments that can be chosen.
### Constraints
- 1≤n≤105.
- 1≤l≤r≤109.
### Example
Input:
56823562525
Output:
2