from scipy.optimize import linprog

# linprogはminimizeを計算するので金額を負値にする
c = [-1000, -2000]
A = [[3 / 4, 2 / 7], [1 / 4, 5 / 7]]
B = list(map(int, input().split()))
bounds = [(0, None), (0, None)]

res = linprog(c, A_ub=A, b_ub=B, bounds=bounds, method='revised simplex')
print(-res.fun)