Given two different points A and B, your task is to find a regular polygon of n sides, passing through these two points, so that the polygon area is minimized. Input There will be at most 100 test cases. Each case contains 5 integers xA, yA, xB, yB, n (0 ≤ xA,yA,xB,yB ≤ 100, 3 ≤ n ≤ 10000), the coordinates of A and B, and the number of sides of the regular polygon. The two points A and B are always different. The last test case is followed by a line with five zeros, which should not be processed. Output For each test case, print the smallest area of the regular polygon to six decimal places. Sample Input 00114 12345 23456 00000 Sample Output 1.000000 5.257311 5.196152