Hi, can someone pls help me find this yaoi/shounen ai.. Uke and seme are childhood friends...

Hi, can someone pls help me find this yaoi/shounen ai.. Uke and seme are childhood friends(I think). One day seme sends a letter to the uke, but the letter was 1 year late so seme thinks that uke doesn't like him [romatically speaking], that's why he became cold towards uke. In the end the uke recieved the letter and accepted seme's feeling and they became a couple~ lol > A < pls, if u know, help me out QwQ thank you