#include <bits/stdc++.h> 
using namespace std;
using ll =long long;
#define all(v) v.begin(),v.end()
 #define rep(i,a,b) for(int i=a;i<b;i++)
#define rrep(i,a,b) for(int i=a;i>=b;i--)


int main() {
ios_base::sync_with_stdio(0); cin.tie(0); 

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

ll count=0;
ll now=-1;
ll next=0;
while(next<N-1) {
    count++;
    ll ma=0;
    for(ll i=now+1;i<=next;i++) {
        ma=max(ma,R[i]);
    }
    now=next;
    next=ma;
}
cout<<count<<endl;
}