Print the [Pascal triangle](https://en.wikipedia.org/wiki/Pascal%27s_triangle) of size $n$.
For example, Pascal triangle of size 5:
```
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
```
### Input
- A single integer $n$.
### Output
- Print the Pascal triangle of size $n$.
### Constraints
- $1 \le n \le 50$.
### Example
Input:
```
4
```
Output:
```
1
1 1
1 2 1
1 3 3 1
```