Four-time world champion M C Mary Kom and L Sarita Devi are sure of at least a bronze medal each after they eased into the semifinals of the Asian Women's Boxing Championship in Astana, Kazakhstan.Mary Kom (46kg) defeated Sri Lanka's Anushka 6-3, while Sarita (51kg) thrashed Ri Hyang Mi of North Korea 10-1. However, Mizoram boxer Venlal Duati (48kg) lost to China's Luo Yujie.The diminutive Mary Kom, who is aiming to better the silver she won in the previous edition of the event, was the first to step into the ring from the Indian team yesterday. Sarita, who was a gold medallist in the last edition, was even more dominant as she out-punched Mi.India has an 11 members team presence at the event where 16 countries are competing. India had finished third with three gold and a couple of silver medals in the last edition held in Guwahati.