#include <iostream>
#include <algorithm>
#include <string>
#include <cstring>
#include <vector>
#include <map>
#include <queue>
#include <cmath>
#include<set>
#include<stack>
#include<deque>
#include<cassert>
#include <bits/stdc++.h>
#define rep(i,n) for (int i=0; i<(int)(n); i++)
using namespace std;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
typedef long long ll;
typedef pair<int,int> P;
using Graph = vector<vector<int>>;
//#define INF 10000000
class UnionFind{
    public:
    vector<int> par;

    UnionFind(int n) : par(n){
        for(int i=0; i<n; i++) par[i] = -1;
    }

    int root(int x){
        if(par[x] == -1) return x;
        int next = par[x];
        return root(next);
    }

    void unite(int x, int y){
        int px = root(x);
        int py = root(y);
        if(px == py) return;
        par[px] = py;
    }

    bool same(int x, int y){
        int px = root(x);
        int py = root(y);
        if(px == py) return true;
        else return false; 
    }
};



bool isPrime(int x){
    bool prime = true;
    for(int i=2; i<x; i++){
        if(x%i == 0){
            prime = false;
            break;
        }
    }
    if(!prime) return false;
    return true;
}


//------------------------------------------------------------------------//

int main(){
    int N; cin >> N;
    vector<int> R(N - 1);
    for (int i = 0; i < N - 1; ++i) cin >> R[i];
    int ans = 0, now = 0;
    while (R[now] != N) {
        now = max_element(R.begin() + now, R.begin() + R[now]) - R.begin();
        ++ans;
    }
    cout << ans + 1 << endl;
}