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();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var n = NN;
        var p = NList;
        var pos = new int[n];
        for (var i = 0; i < n; ++i)
        {
            --p[i];
            pos[p[i]] = i;
        }
        var ans = 0;
        for (var i = 0; i < n; ++i)
        {
            var snum = p[i];
            while (snum != i)
            {
                var tnum = p[i] - 1;
                var spos = pos[snum];
                var tpos = pos[tnum];
                (p[spos], p[tpos], pos[snum], pos[tnum]) = (p[tpos], p[spos], pos[tnum], pos[snum]);
                --snum;
                ++ans;
            }
        }
        WriteLine(ans);
    }
}