CF367B Sereja ans Anagrams

Sereja has two sequences $ a $ and $ b $ and number $ p $ . Sequence $ a $ consists of $ n $ integers $ a_{1},a_{2},...,a_{n} $ . Similarly, sequence $ b $ consists of $ m $ integers $ b_{1},b_{2},...,b_{m} $ . As usual, Sereja studies the sequences he has. Today he wants to find the number of positions $ q $ $ (q+(m-1)·p=1) $ , such that sequence $ b $ can be obtained from sequence $ a_{q},a_{q+p},a_{q+2p},...,a_{q+(m-1)p} $ by rearranging elements. Sereja needs to rush to the gym, so he asked to find all the described positions of $ q $ .

The first line contains three integers $ n $ , $ m $ and $ p $ $ (1

In the first line print the number of valid $ q $ s. In the second line, print the valid values in the increasing order.