Rahab, the harlot & Ruth, the Moabitess were ancestors of the Lord Jesus Christ.  Rahab was the mother-in-law of Ruth, and Ruth was Rahab's daughter-in-law.  Rahab, the harlot was married to Salmon, the father of Boaz who married Ruth, the Moabitess, who was a descendant of Moab, the son of the oldest of Lot's daughters and the son of Lot himself. Both the Moabites and the Ammonites even until their 10th generation were not allowed to enter into the congregation of the Lord according to Deut. 23:3-4. 

Deut. 23:3-4, "An Ammonite or Moabite shall not enter into the congregation of the LORD; even to their tenth generation shall they not enter into the congregation of the LORD for ever: Because they met you not with bread and with water in the way, when ye came forth out of Egypt; and because they hired against thee Balaam the son of Beor of Pethor of Mesopotamia, to curse thee."

There is no way of knowing if there are 10 generations between Moab and Ruth because all Moab's descendants are not listed in the Bible although there are 10 generations from Isaac, a much younger cousin of Lot, down through Boaz.  However, Ruth displayed her faith and so did Rahab her mother-in-law according to the following Bible verses:

Ruth 1:16-17, "And Ruth said, Intreat me not to leave thee, or to return from following after thee: for whither thou goest, I will go; and where thou lodgest, I will lodge: thy people shall be my people, and thy God my God: Where thou diest, will I die, and there will I be buried: the LORD do so to me, and more also, if ought but death part thee and me."

Hebrews 11:31, "By faith the harlot Rahab perished not with them that believed not, when she had received the spies with peace."

James 2:25, "Likewise also was not Rahab the harlot justified by works, when she had received the messengers, and had sent them out another way?"

Then there is King David who was another ancester of the Lord Jesus.  King David was both an adulterer with Bath-Sheba also called Bath-Shua, and he was a murderer of Bath-Sheba's husband Uriah.  Their son Nathan was an ancestor of Mary, the mother of Jesus and their son Solomon was an ancestor of Joseph, who was Jesus' stepfather.  However, King David confessed his sin. 

2 Samuel 12:13, "And David said unto Nathan, I have sinned against the LORD. And Nathan said unto David, The LORD also hath put away thy sin; thou shalt not die."

There were 10 generations from Adam thru Noah, 10 generations from Shem, Noah's son, thru Abraham, and another 10 generations from Isaac, Abraham's son thru Boaz. There are another 30 generations from Obed, Boaz & Ruth's son, down thru Jesus which includes Solomon, King David's son and Joseph, the step-father of Jesus.  This is a total of 60 generations beginning with Adam.  

As for Mary's ancestors, there are another 54 generations from Obed, Boaz & Ruth's son down thru Jesus which includes Nathan, King David's son down thru Jesus.  This is a total of 84 generations beginning with Adam.