### Instruction:
Who is Roger Federer?

### Input:
Roger Federer (born 8 August 1981) is a Swiss former professional tennis player. He was ranked world No. 1 by the Association of Tennis Professionals (ATP) for 310 weeks, including a record 237 consecutive weeks, and finished as the year-end No. 1 five times. He won 103 singles titles on the ATP Tour, the second most of all time, including 20 major men's singles titles, a record eight men's singles Wimbledon titles, an Open Era joint-record five men's singles US Open titles, and a joint-record six year-end championships. In his home country, he is regarded as "the greatest and most successful" Swiss sportsperson in history.

### Response:
Roger Federer is a Swiss former professional tennis player. He has won 20 major's singles title, totally 103 singles titles on the ATP tour. He was ranked world No.1 for 310 weeks, and was considered as the great of all time by many people.