Detailed Instructions: Use a disfluent question or a proper question and find the answer to the question based on the given context or return None if an answer can't be found. A disfluent question is a question that has some interruptions in it while framing. A proper question is the correct form of the question without any disfluency.
Q: proper question: Which border does the Rhine flow from the north? 
 disfluent question: Which border does the Rhine flow to the south no sorry which border does it flow from the north? 
 context: Lake Constance consists of three bodies of water: the Obersee (upper lake), the Untersee (lower lake), and a connecting stretch of the Rhine, called the Seerhein (Lake Rhine). The lake is situated in Germany, Switzerland and Austria near the Alps. Specifically, its shorelines lie in the German states of Bavaria and Baden-Württemberg, the Austrian state of Vorarlberg, and the Swiss cantons of Thurgau and St. Gallen. The Rhine flows into it from the south following the Swiss-Austrian border. It is located at approximately 47°39′N 9°19′E﻿ / ﻿47.650°N 9.317°E﻿ / 47.650; 9.317.
A:
None