using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var n = NN;
        var a = NList;
        var set = new HashSet<int>(a);
        var list = new List<int>(set);
        list.Sort();
        var dic = new Dictionary<int, int>();
        for (var i = 0; i < list.Count; ++i) dic[list[i]] = i;
        var ans = 0L;
        var ft = new FenwickTree(list.Count);
        for (var i = 0; i < n; ++i)
        {
            ans += i - ft.Sum(dic[a[i]]);
            ft.Add(dic[a[i]], 1);
        }
        WriteLine(ans);
    }
    class FenwickTree
    {
        int size;
        long[] tree;
        public FenwickTree(int size)
        {
            this.size = size;
            tree = new long[size + 2];
        }
        public void Add(int index, long value)
        {
            ++index;
            for (var x = index; x <= size; x += (x & -x)) tree[x] += value;
        }
        /// <summary>先頭からindexまでの和(include index)</summary>
        public long Sum(int index)
        {
            if (index < 0) return 0;
            ++index;
            var sum = 0L;
            for (var x = index; x > 0; x -= (x & -x)) sum += tree[x];
            return sum;
        }
        public long Get(int index)
        {
            if (index == 0) return Sum(0);
            return Sum(index) - Sum(index - 1);
        }
        /// <summary>Sum(x) >= value となる最小のxを求める</summary>
        // 各要素は非負であること
        public int LowerBound(long value)
        {
            if (value < 0) return -1;
            var x = 0;
            var b = 1;
            while (b * 2 <= size) b <<= 1;
            for (var k = b; k > 0; k >>= 1)
            {
                if (x + k <= size && tree[x + k] < value)
                {
                    value -= tree[x + k];
                    x += k;
                }
            }
            return x;
        }
        public long[] Debug()
        {
            var ans = new long[size];
            for (var i = 0; i < size; ++i) ans[i] = Get(i);
            return ans;
        }
    }
}