import sys; input = sys.stdin.buffer.readline
sys.setrecursionlimit(10**7)
from collections import defaultdict
con = 10 ** 9 + 7; INF = float("inf")

def getlist():
	return list(map(int, input().split()))

#処理内容
def main():
	a, b, c, d, e, f = getlist()
	r2 = (f - e) / a + ((c ** 2 + d ** 2) / 4 / (a ** 2))
	r = r2 ** 0.5
	print(r)




if __name__ == '__main__':
	main()