**[Codeforces Round #827 (Div. 4)](https://codeforces.me/contest/1742)**
**[Codeforces Round #817 (Div. 4)](https://codeforces.me/contest/1722)**
**[Codeforces Round #806 (Div. 4)](https://codeforces.me/contest/1703)**
**[Codeforces Round #799 (Div. 4)](https://codeforces.me/contest/1692)**
**[Codeforces Round #790 (Div. 4)](https://codeforces.me/contest/1676)**
**[Codeforces Round #784 (Div. 4)](https://codeforces.me/contest/1669)**
**[Codeforces Round #640 (Div. 4)](https://codeforces.me/contest/1352)**