B"Vasiliy lives at point (a, xe2 x80 x89b) of the coordinate plane. He is hurrying up to work so he wants to get out of his house as soon as possible. New app suggested n available Beru-taxi nearby. The i-th taxi is located at point (xi, xe2 x80 x89yi) and moves with a speed vi. Consider that each of n drivers will move directly to Vasiliy and with a maximum possible speed. Compute the minimum time when Vasiliy will get in any of Beru-taxi cars. The first line of the input contains two integers a and b ( xe2 x80 x89- xe2 x80 x89100 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89a, xe2 x80 x89b xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89100) -- coordinates of Vasiliy's home. The second line contains a single integer n (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89n xe2 x80 x89 xe2 x89 xa4 xe2 x80 x891000) -- the number of available Beru-taxi cars nearby. The i-th of the following n lines contains three integers xi, yi and vi ( xe2 x80 x89- xe2 x80 x89100 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89xi, xe2 x80 x89yi xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89100, 1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89vi xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89100) -- the coordinates of the i-th car and its speed. It's allowed that several cars are located at the same point. Also, cars may be located at exactly the same point where Vasiliy lives. Print a single real value -- the minimum time Vasiliy needs to get in any of the Beru-taxi cars. You answer will be considered correct if its absolute or relative error does not exceed 10 xe2 x80 x89- xe2 x80 x896. Namely: let's assume that your answer is a, and the answer of the jury is b. The checker program will consider your answer correct, if . In the first sample, first taxi will get to Vasiliy in time 2, and second will do this in time 1, therefore 1 is the answer. In the second sample, cars 2 and 3 will arrive simultaneously. "...