When did the North-South cp start?

The famous detective academy's North and South cp started from the first season, and Wen Tao participated in the second season!

In fact, Puyixing and Guo Wentao have a sense of cp, which happened before they went to a famous detective college. It's time for two people to record one stop to the end, because one is the school grass of Nanjing University and the other is the school grass of Peking University, so they form the North-South cp! Later, after attending a prestigious school, the two became friends.