#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)
#define Inf 1000000001


int main(){
	
	int n;
	cin>>n;
	vector<int> r(n-1);
	rep(i,n-1){
		cin>>r[i];
		r[i]--;
	}
	
	int cur = 0;
	int maxi = 0;
	int ans = 0;
	rep(i,n-1){
		maxi = max(maxi,r[i]);
		if(cur == i){
			cur = maxi;
			ans++;
		}
	}
	cout<<ans<<endl;
	
	return 0;
}