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 a = NList;
        var cum = new int[n - 1];
        cum[0] = a[0];
        for (var i = 1; i < a.Length; ++i) cum[i] = Math.Max(cum[i - 1], a[i]);
        var max = 1;
        var ans = 0;
        while (max < n)
        {
            max = cum[max - 1];
            ++ans;
        }
        WriteLine(ans);
    }
}