#include <bits/stdc++.h>
#define sz(x) ((int)x.size())
#define PB push_back
#define all(x) x.begin(),x.end()
using namespace std;
const int N = 1000100;
const int PW = 20;
const int oo = 2e9;
int a[N], n, f[N], kol[N], pref[N], vl, sp[N][PW], prec[N], pr[N], nt[N];
vector<int> vc;
bool ok(int l, int r){
int kl = pref[r] - pref[l];
if (kl > 0) return 0;
return (a[r] <= vl);
}
int Min(int l, int r){
int len = r - l + 1;
return min(sp[l][prec[len]], sp[r - (1 << prec[len]) + 1][prec[len]]);
}
void update(int ps){
sp[ps][0] = f[ps];
for (int po = 1; po < PW; po++){
if (ps + (1 << po) - 1 >= n) break;
sp[ps][po] = min(sp[ps][po - 1], sp[ps + (1 << (po - 1))][po - 1]);
}
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
// freopen("in.txt","r",stdin);
cin >> n;
for (int i = 0; i < n; i++) {
cin >> a[i];
kol[a[i]]++;
}
int pre = 0;
for (int i = 1; i < N; i++){
pr[i] = pre;
if (kol[i] > 0)
pre = i;
}
pre = N - 1;
for (int i = pre - 1; i > 0; i--){
nt[i] = pre;
if (kol[i] > 0)
pre = i;
}
pref[0] = 0;
for (int i = 1; i < n; i++)
pref[i] = pref[i - 1] + bool(a[i] < a[i - 1]);
prec[0] = -1;
for (int i = 1; i <= n; i++)
prec[i] = prec[i >> 1] + 1;
f[n] = 0;
for (int it = n - 1; it >= 0; it--){
kol[a[it]]--;
if (kol[a[it]] == 0){
pr[nt[a[it]]] = pr[a[it]];
nt[pr[a[it]]] = nt[a[it]];
}
vl = nt[a[it]];
int l = it, r = n - 1;
while (l < r){
int md = (l + r + 1) >> 1;
if (ok(l, md))
l = md;
else r = md - 1;
}
f[it] = Min(it + 1, l + 1) + 1;
update(it);
}
cout << f[0];
return 0;
}
