G. Shortest pathtime limit per test1 secondmemory limit per test256 megabytesinputstandard inputoutputstandard outputYou are given N points on an infinite plane with the Cartesian coordinate system on it. N-1 points lay on one line, and one point isn't on that line. You are on point K at the start, and the goal is to visit every point. You can move between any two points in a straight line, and you can revisit points. What is the minimum length of the path? InputThe first line contains two integers: N (3 \leq N \leq 2*10^5) - the number of points, and K (1 \leq K \leq N) - the index of the starting point.Each of the next N lines contain two integers, A_i, B_i (-10^6 \leq A_i, B_i \leq 10^6) - coordinates of the i-th point.OutputThe output contains one number - the shortest path to visit all given points starting from point K. The absolute difference between your solution and the main solution shouldn't exceed 10^-6;ExampleInput
5 2
0 0
-1 1
2 -2
0 1
-2 2
Output
7.478709NoteThe shortest path consists of these moves: 2 -> 5 5 -> 4 4 -> 1 1 -> 3 There isn't any shorter path possible.
5 2
0 0
-1 1
2 -2
0 1
-2 2

7.478709
['brute force', 'geometry', 'math', 'shortest paths', '*2700']