import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        
        Scanner sc = new Scanner(System.in);
        
        int n = sc.nextInt();
        int[] rs = new int[n];
        for(int i = 0 ; i < n - 1 ; i++){
            rs[i] = sc.nextInt();
        }
        rs[n-1] = n;
        
        int now = 1;
        int ans = 0;
        while(rs[now-1] != n){
            int max = -1;
            for(int i = now, len = rs[now-1] ; i < len ; i++){
                max = Math.max(max , rs[i-1]);
            }
            now = max;
            ans++;
        }
        
        System.out.println(ans+1);
    }
}