def parse(inFile):
    return tuple(inFile.getFloats())

from math import sqrt, asin, pi

def integralOfSqrtOneMinusXSquared(x):
    return (sqrt(1 - x * x) * x + asin(x)) / 2

def areaOfRectangleInsideUnitCircle(n,n2,x,x2):
    # rectangle is [n,x] x [n2,x2]
    if (n * n + n2 * n2) >= 1: return 0
    if (x * x + x2 * x2) <= 1: return (x2 - n2) * (x - n)
    if (n * n + x2 * x2) >= 1:
        x2 = sqrt(1 - n * n)
    if (n2 * n2 + x * x) >= 1:
        x = sqrt(1 - n2 * n2)
    if (x * x + x2 * x2) <= 1: return (x2 - n2) * (x - n)
    m = sqrt(1-x2*x2)
    m2 = sqrt(1 - x * x)
    return (m - n) * (x2 - n2) + (m2 - n2) * (x - m) + integralOfSqrtOneMinusXSquared(x) - integralOfSqrtOneMinusXSquared(m) - (x - m) * m2

def solve2(r,g):
    tot = 2 * r + g
    area = 0
    i = 0
    while (i <= 1 + r):
        n = max(i - r, 0)
        x = min(i + r, 1)
        area += 2 * (integralOfSqrtOneMinusXSquared(x) - integralOfSqrtOneMinusXSquared(n))
        j = 0
        while (j <= 1 + r):
            n2 = max(j - r, 0)
            x2 = min(j + r, 1)
            area -= areaOfRectangleInsideUnitCircle(n,n2,x,x2)
            j += tot
        i += tot
    return area * 4

def solve1(R,t,r,g):
    return (((2 * R - t) * t * pi)  + solve2(r/(R-t),g/(R-t)) * (R - t) * (R - t)) / (pi * R * R)

def solve((f,R,t,r,g)):
    if (R - t < f): return 1.0
    if (g < 2 * f): return 1.0
    return "%.7f" % solve1(R,t+f,r+f,g-2*f)

if __name__ == "__main__":
    from GCJ import GCJ
    GCJ(parse, solve, "/Users/lpebody/gcj/2008_q/", "c").run()