import "../../mod/libfwdio.so"

sum_inner(i32 s, i32 n, (i32) res)
{
	if n <= 0 as i32 {
		res(s);
	} else {
		sum_inner(s + n, n - 1 as i32, res);
	}
}

sum(i32 n, (i32) res)
{
	sum_inner(0 as i32, n, res);
}

main()
{
	sum(1000000 as i32) => i32 s;
	if s != 1784293664 as i32 {
		fwdprint_str("expected 1784293664, got ");
		fwdprint_i64(s as i64);
		fwdprint_nl();
	} else {
		fwdprint_str("OK");
		fwdprint_nl();
	}
}