int main ()
{
	int n, m, i, j, count, p, xh;
	int a[310]; // a??? ????????????
	int b[310]; // b???? ??????? ?????????????i???????????
    // ?????????????count?1
	while (cin)
	{
		cin >> n >> m;
		if ((n == 0) && (m == 0)) return 0;
		for (i = 1; i <= n; i++) a[i] = 1;
		count = n;
		p = 1;
		while (count != 1)
		{
			// ????????b??
			xh = 1;
			while (xh <= m)
			{
				if (a[p] == 1) xh++;
				if (p <= n - 1) p++;
				else p = (p + 1) % n;
			}
			if (p == 1) a[n] = 0;
			else a[p - 1] = 0;
			count = count - 1;
		}
		for (i = 1; i <= n; i++)
		{
			if (a[i] == 1) cout << i << endl;
		}
	}
	return 0;
}