Stretches with no repeats

Problem

A warehouse scans n items in a row. A stretch of k items is clean when no item code appears twice in it. Count the clean stretches.

Example

Input

6 3
1 2 1 3 4 4

Output

The stretches 2 1 3 and 1 3 4 are clean. The others repeat a code.

Try the problem first. Open one hint at a time.

Hint 1

A stretch is clean when the number of different codes equals k.

Hint 2

A set removes repeated codes.

Write your Python code, run it on the examples and submit it to hidden tests.