import random	
import math

def annealing_initialze():
  cost_max=0
  for ii in range(3000):
    for jj in range(3000):
        vec=[(C+D)*ii/2000,(C+D)*jj/2000]
        stock_c=C-0.75*vec[0]-2/7*vec[1]
        stock_d=D-0.25*vec[0]-5/7*vec[1]
        if stock_c>=0 and stock_d>=0:
            if cost_max<= costf(vec):
                cost_max= costf(vec)
                vect=vec[:]
  return vect


def annealingoptimize(T=12000, cool=0.99993, step=0.005):
    dimension=2
    
    vec=[A,B]
    newvec = vec[:]
    while T > 0.0001:
        i = random.randint(0, dimension-1)
        dir = random.random()
        dir = (dir - 0.5) * step

        if i==0:
            stock_c=C-0.75*(vec[0]+dir)-2/7*vec[1]
            stock_d=D-0.25*(vec[0]+dir)-5/7*vec[1]
            if stock_c<0 or stock_d<0 or vec[0]+dir<0:
                newvec[i] = vec[i]
            else:
                newvec[i] = vec[i] + dir

        else:
            stock_c=C-0.75*vec[0]-2/7*(vec[1]+dir)
            stock_d=D-0.25*vec[0]-5/7*(vec[1]+dir)
            if stock_c<0 or stock_d<0 or vec[1]+dir<0:
                newvec[i] = vec[i]
            else:
                newvec[i] = vec[i] + dir

        newcost = costf(newvec)
        cost = costf(vec)
        p = pow(math.e, -abs(newcost - cost) / T)
        if(newcost > cost or random.random() < p):
            vec[i] = newvec[i]
        T = T * cool
    return vec
	
def costf(vec):
    return (1000*vec[0]+2000*vec[1])

C,D=[int(i) for i in input().split()]
A,B=annealing_initialze()
#print(A,B)


ans=0
k_min=[]
for i in range(4):
    kkk=annealingoptimize()
    cost=costf(kkk)
    ans=max(ans,cost)
print(ans)