#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>
#include <complex>
#include <cassert>

using namespace std;
using ll = long long;

int main(){

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

    while(now != N-1){
        now = R[now];
        ans++;
    }

    cout << ans << endl;

    return 0;
}