#include <bits/stdc++.h>

using namespace std;

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;
}