mod = 1000000007
eps = 10**-9


def main():
    import sys
    input = sys.stdin.readline

    a, b, c, d, e, f = map(int, input().split())
    if a < 0:
        a, b, c, d, e, f = -a, -b, -c, -d, -e, -f
    x0 = -c / (a*2)
    y0 = -d / (b*2)
    ok = 10000000
    ng = 0
    mid = (ok+ng)/2
    while ok - ng > 10**-5:
        y = y0 + mid
        x = x0
        val = a*x*x + b*y*y + c*x + d*y + e
        if val > f:
            ok = mid
        else:
            ng = mid
        mid = (ok+ng)/2
    print(ok)


if __name__ == '__main__':
    main()