#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll=long long;
using Graph=vector<vector<pair<int,ll>>>;
#define INF 1000000000000000000
#define MOD 998244353
#define MAX 1000000

int main(){
  int N;
  cin>>N;
  vector<int> R(N-1);
  for(int i=0;i<N-1;i++){
    cin>>R[i];
    R[i]--;
  }

  int ans=0;
  int current=0;
  int next=0;
  for(int i=0;i<N-1;i++){
    next=max(next,R[i]);
    if(i==current){
      ans++;
      current=next;
    }
  }
  cout<<ans<<'\n';
}