题解 | #Grading#

def m(a, b):
    if a > b:
        return a
    else:
        return b
def m3(a, b, c):
    s = []
    s.append(a)
    s.append(b)
    s.append(c)
    return max(s)

def Grading(p, t, g1, g2, g3, gj):
    if abs(g1-g2) <= t:
        return round(((g1+g2) / 2), 1)
    else:
        if abs(g1-g3) <= t and abs(g2-g3) <= t:
            return m3(g1, g2, g3)

        elif abs(g1-g3) <= t and abs(g1-g3) > t or abs(g1-g3) > t and abs(g1-g3) <= t:
            k = m(abs(g1-g3), abs(g2-g3))
            return round(k + g3 +g3, 1)
        
        else:
            return gj

while True:
    try:
        p, t, g1, g2, g3, gj = map(int, input().split())
        res = Grading(p, t, g1, g2, g3, gj)
        print(res)
    except:
        break