This problem is in Contest(s) below:
Contest 1227:春周六晚C++第五期
Contest 1216:2023春季周日早
Contest 1223:2023春周日晚C++第五期
Contest 1399:2025春周日晚c2
Contest 1396:2025春周六下c2
Contest 1174:2022秋周日上c++第三期（平阳）
Contest 1406:2025春c++ c3