method f1(a b)
	return a - (-3 * b);
end;

method f2(a b)
	return a - (2 * b);
end;

method f3(a b)
	return a - (5 * b);
end;

method  f(a b c d)
        return a - (8 * (b - (-4 * (c - (-3 * d)))));
end;