Odpowiedź :
x, k = input().split()
x = int(x)
k = int(k)
if x >= 7 * k:
print(7000 * k)
elif 2 * x >= 7 * k:
print(3500 * k)
elif 4 * x >= 7 * k:
print(1750 * k)
else:
print(0)
x, k = input().split()
x = int(x)
k = int(k)
if x >= 7 * k:
print(7000 * k)
elif 2 * x >= 7 * k:
print(3500 * k)
elif 4 * x >= 7 * k:
print(1750 * k)
else:
print(0)