#!/usr/bin/env python3
# %%
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

eps = 1e-8

# %%
C, D = map(int, read().split())


# %%
def gen_cand(C, D):
    b = (3 * D - C) * 7 / 13
    a = 4 * D - 20 * b / 7
    yield (a, b)
    yield (4 * C / 3, 0)
    yield (4 * D, 0)
    yield (0, 7 * C / 2)
    yield (0, 7 * D / 5)


# %%
answer = 0
for a, b in gen_cand(C, D):
    if a < 0 or b < 0:
        continue
    if (3 / 4) * a + (2 / 7) * b > C + eps:
        continue
    if (1 / 4) * a + (5 / 7) * b > D + eps:
        continue
    x = 1000 * a + 2000 * b
    if answer < x:
        answer = x

# %%
print(answer)