__author__ = 'Damjan'
import math

def A1(s):
    if s>=60:
        return 1.0
    elif s<60:
        return 1.0/pow(math.e,(60-math.fabs(s)))
    else:
        return -1.0

def A2(s):
    if s<=10:
        return 1.0
    elif s>10:
        return 1.0/(1+pow(math.e,math.fabs(10-s)))
    else:
        return -1.0

def B1(s):
    if s>=0.8:
        return 1.0
    elif s<0.8:
        return 1.0/(1+pow(0.2+s,3))
    else:
        return -1/0

def B2(s):
    if s<=0.1:
        return 1.0
    elif s>0.1:
        return 1/(1+pow(0.9+s,2))
    else:
        return -1.0

def Rule1_min(s,e):
    return min(A2(s),B2(e))

def Rule2_min(s,e):
    return min(A1(s),B2(e))

def Rule3_min(s,e):
    return min(A1(s),B1(e))

def COG(w1,w2,w3,c1,c2,c3):
    return (w1*c1+w2*c2+w3+c3)/(w1+w2+w3)
def C1():
    return 2000.0
def C2():
    return 500.0
def C3():
    return 100.0

if __name__ == "__main__":
    t=input()
    h=input()
    v1=Rule1_min(t,h)
    v2=Rule2_min(t,h)
    v3=Rule3_min(t,h)
    b1=C1()
    b2=C2()
    b3=C3()
    print COG(v1,v2,v3,b1,b2,b3)