PROGRAMMING:Find the number of elements in the specified layer
Enter a nested list, and then enter the number of layers to find the number of digital elements of the layer.
###Input format:
First line input list
Enter the number of layers in the second line
###Output format:
Output the number of elements in a row
###Input example:
Here is a set of inputs. For example:
```in
[1,2,[3,4,[5,6],7],8]
three
```
###Output example:
The corresponding output is given here. For example:
```out
two
```
answer：If there is no answer, please comment
###Input format:
First line input list
Enter the number of layers in the second line
###Output format:
Output the number of elements in a row
###Input example:
Here is a set of inputs. For example:
```in
[1,2,[3,4,[5,6],7],8]
three
```
###Output example:
The corresponding output is given here. For example:
```out
two
```
answer：If there is no answer, please comment