public class BIT  
{
	private readonly long _max;
	private readonly long[] _tree;

	public BIT(long max)
	{
		_max = max;
		_tree = new long[max];
	}

	public long get(int idx)
	{
		return query(idx) - query(idx - 1);
	}

	public void set(int idx, long val)
	{
		long curr = get(idx);
		while (idx <= _max)
		{
			_tree[idx] += val-curr;
			idx += (idx & -idx);
		}
	}

	public long query(int idx)
	{
		long sum = 0;
		while (idx > 0)
		{
			if (idx < _max)
			{
				sum += _tree[idx];
			}

			idx -= (idx & -idx);
		}

		return sum;
	}
}

public static long solve(List<long> arr)
{
	var max = arr.Count;
	long[] h = new long[max];
	var S = new SortedSet<long>();
	var m = new Dictionary<long, long>();
	var a = new BIT(max);
	var b = new BIT(max);
	var c = new BIT(max);

	foreach (var l in arr)
	{
		S.Add(l);
	}

	long cnt = 1;
	foreach (var l in S)
	{
		m.Add(l, cnt++);
	}

	for (int i = 0; i < arr.Count; i++)
	{
		int indx = Convert.ToInt32(m[arr[i]]);
		h[i] = m[arr[i]];
		a.set(indx, 1);
		b.set(indx, a.query(indx - 1));
		c.set(indx, b.query(indx - 1));
	}

	return c.query(max);

}