 Complete the following phrase:  In Sangin, 37 relieved the 40 Commando of the British Royal Marines in July 2010 and began clearing operations in some of the most dangerous areas of Afghanistan, where they began operation Sangin Sunrise, which cleared all the tree lines that led to the Helmand River, to prepare the area for clearing operations by 3rd Battalion, 5th Marine Regiment 35. 35 relieved 37 in September 2010, and began clearing operations in early October 2010 under the command of LtCol Jason Morris. They conducted the clearing operations in the Sangin District of Helmand Province, Afghanistan in support of the 