Country A and B each have 5,000 units of labour. In Country A, one unit of labour can produce 8 loaves of bread or 48 kilograms of butter. In Country B, one unit of labour can produce 11 loaves of bread or 37 kilograms of butter. Suppose Country B follows its comparative advantage in deciding what to produce and trades with Country A at a trade price of 4.9 kilograms of butter per loaf of bread, and Country B consumes 32000 loaves of bread at home, then Country B's gain from trade would be ____________kilograms of butter.