With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: The 2017 Open Championship is a tennis championship.
text_B: The Open Championship , often referred to as The Open or the British Open , is the oldest of the four major championships in professional golf .. major championships. Men's major golf championships. golf. golf. Held in the United Kingdom , it is administered by The R&A and is the only major outside the United States .. United Kingdom. United Kingdom. The R&A. R&A. United States. United States. The Open is currently the third major of the year , between the U.S. Open and the PGA Championship , and is played in mid-July .. U.S. Open. U.S. Open ( golf ). PGA Championship. PGA Championship. The current champion is Henrik Stenson , who won the 145th Open at Royal Troon in 2016 with a record-breaking score of − 20 .. Henrik Stenson. Henrik Stenson. 2016 Open Championship. 145th Open. 2016 Open Championship
related.