using static System.Math;
using System;

public class Hello
{
    static void Main()
    {
        var n = int.Parse(Console.ReadLine().Trim());
        string[] line = ("0 " + Console.ReadLine().Trim()).Split(' ');
        var r = Array.ConvertAll(line, int.Parse);
        getAns(n, r);
    }
    static void getAns(int n, int[] r)
    {
        var step = 0;
        var p = 1;
        while (p < n)
        {
            var imax = r[p];
            var nextmax = 0;
            for (int i = p; i <= imax; i++) nextmax = Max(nextmax, r[p]);
            p = nextmax;
            step++;
        }
        Console.WriteLine(step);
    }
}