#! /usr/bin/env python3

def f(A, C, D):
    c, d = C-A*(3/4), D-A*(1/4)
    b = min(c/(2/7), d/(5/7))
    return A+b*2

def main():
    C, D = map(int, input().split())
    A = min(C/(3/4), D/(1/4))
    ans = A
    n = 0
    for i in range(int(A)+1):
        a = f(i, C, D)
        if a > ans and i <= A:
            ans = a
            n = i
    for x in range(16):
        m = 0
        for i in range(10):
            j = i/(10**x)
            a = f(n+j, C, D)
            if a > ans and n+j <= A:
                ans = a
                m = j
        n += m
    
    print(ans*1000)
if __name__ == '__main__':
    main()