/* fibonacci */

/* F_0 = 0 */
/* F_1 = 1 */
/* F_n = F_{n-1} + F_{n-2} */

struct f0 f1 f2 f3 f4 f5 f6 f7 f8 f9 end;

method fib(x)
	if x < 0 then return -1; end;	f0 := 0;
	if x < 1 then return f0; end;	f1 := 1;
	if x < 2 then return f1; end;	f2 := f0-(0-f1);
	if x < 3 then return f2; end;	f3 := f1-(0-f2);
	if x < 4 then return f3; end;	f4 := f2-(0-f3);
	if x < 5 then return f4; end;	f5 := f3-(0-f4);
	if x < 6 then return f5; end;	f6 := f4-(0-f5);
	if x < 7 then return f6; end;	f7 := f5-(0-f6);
	if x < 8 then return f7; end;	f8 := f6-(0-f7);
	if x < 9 then return f8; end;	f9 := f7-(0-f8);
	return f9;
end;