extern "C" int *find_pairs(int n, int m, int u[], int v[])
{
	using namespace std;
	auto check = [](int x1, int y1, int x2, int y2) -> bool
	{ return x1 != x2 && x1 != y2 && y1 != x2 && y1 != y2; };
	int *ret = (int *)malloc(m * sizeof(int));
	vector<int> ans(m + 1);
	vector<pair<int, int>> points(m + 1);
	for (int i = 1; i <= m; i++)
		points[i].first = u[i - 1], points[i].second = v[i - 1];
	auto solve = [&ans, m, &points, &check](int id1, int id2) -> void
	{
		// assert(check(points[id1].first, points[id1].second, points[id2].first, points[id2].second));
		for (int i = 1; i <= m; i++)
			if (check(points[i].first, points[i].second, points[id1].first, points[id1].second))
				ans[i] = id1;
		for (int i = 1; i <= m; i++)
			if (check(points[i].first, points[i].second, points[id2].first, points[id2].second))
				ans[i] = id2;
		for (int i = 1; i <= m; i++)
			for (int j = 1; j <= m && ans[i] == 0; j++)
				if (check(points[i].first, points[i].second, points[j].first, points[j].second))
					ans[i] = j;
	};
	bool flag = false;
	for (int i = 2; i <= m && !flag; i++)
		if (check(points[i].first, points[i].second, points[1].first, points[1].second))
			solve(1, i), flag = true;
	if (!flag)
	{
		int id;
		for (id = 1; id <= m; id++)
			if (points[id].first != points[1].first && points[id].second != points[1].first)
				break;
		if (id <= m)
		{
			auto fd = [&points, m](int x, int y) -> int
			{
				for (int i = 1; i <= m; i++)
					if (x == points[i].first && y == points[i].second)
						return i;
				return 0;
			};
			int res1 = fd(points[1].first, points[id].second);
			int res2 = fd(points[id].second, points[1].first);
			if (res1)
			{
				for (int i = 1; i <= m && !flag; i++)
					if (check(points[res1].first, points[res1].second, points[i].first, points[i].second))
						solve(i, res1), flag = true;
			}
			else if (res2)
			{
				for (int i = 1; i <= m && !flag; i++)
					if (check(points[res2].first, points[res2].second, points[i].first, points[i].second))
						solve(i, res2), flag = true;
			}
		}
	}
	for (int i = 1; i <= m; i++)
		ret[i - 1] = ans[i] - 1;
	return ret;
}