The second mini album from Cortis stormed past 2 million sales mark in four days, label Big Hit Music said Friday. EP “Greengreen” was released Monday and was an instant million-seller, and exceeded 2 million as of Thursday. The rookie boy group’s debut set, “Color Outside the Lines,” reached 1 million in accumulated sales in three months, and 2 million in six months. Main track “Redred” rose to No. 3 on Melon’s Top 100 and earned the fivesome its first and second trophies on television music ch