mod = 1000000007
eps = 10**-9


def main():
    import sys
    import math
    input = sys.stdin.readline
    
    a, b, c, d, e, f = map(int, input().split())
    assert a == b
    print(math.sqrt((c*c + d*d + 4*a*(f-e))/(4*a*a)))


if __name__ == '__main__':
    main()