TODO: https://codeforces.com/blog/entry/85714
TULIPS: https://www.youtube.com/watch?v=D63l9u1-nBI and https://www.youtube.com/watch?v=DTCvKPdWH2M
https://discuss.codechef.com/t/tulips-editorial/12281
https://www.codechef.com/viewsolution/48821395 - Using SQRT decomposition
TODO: https://ioi2018.jp/wp-content/tasks/contest1/werewolf-review.pdf