#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
//const long nPrime = 1000000007;
//const long nPrime = 998244353;
typedef long long ll;
int main() {
    ll n;
    cin >> n;
    vector<ll> viAns(n+1,1e9);
    viAns[1]=0;
    for(ll i = 0; i < n; i++){
        ll x;
        cin >> x;
        viAns[x] = min(viAns[x], viAns[i+1]+1);
    }
    cout << viAns[n] <<endl;
    return 0;
}