#include "bits/stdc++.h"
using namespace std;
const int N = (int) 1e6 + 22;
mt19937 gen(22);
int p[N], mn[N];
int get(int v) {
return v == p[v] ? v : p[v] = get(p[v]);
}
void merge(int v, int u) {
v = get(v), u = get(u);
mn[u] = min(mn[u], mn[v]);
p[v] = u;
}
void solve() {
iota(p, p + N, 0);
iota(mn, mn + N, 0);
int n = gen() % 10 + 1;
cin >> n;
vector<int> a(n);
vector<int> cnt(N, 0), prv(N, -1);
for (int i = 0; i < n; i++) {
// a[i] = gen() % 10 + 1;
cin >> a[i];
cnt[a[i]]++;
}
for (int i = 0; i + 1 < N; i++) {
if (!cnt[i]) {
merge(i, i + 1);
}
}
// cout << n << endl;
// for (int i = 0; i < n; i++) {
// cout << a[i] << " ";
// }
// cout << endl;
{
auto b = a;
std::sort(b.begin(), b.end());
for (int i = 1; i < n; i++) {
if (b[i] != b[i - 1]) {
prv[b[i]] = b[i - 1];
}
}
}
int ans = 0;
while (!a.empty()) {
ans++;
int j = (int) a.size() - 1, c = 1;
bool is_first = true;
while (j > 0) {
// cout << j << endl;
if (a[j - 1] == a[j]) {
j--;
c++;
continue;
}
if (a[j - 1] != prv[a[j]]) {
break;
}
if (is_first) {
is_first = false;
j--;
c = 1;
continue;
}
if (c == cnt[a[j]]) {
j--;
c = 1;
} else {
break;
}
}
// cout << j << " " << a.size() << endl;
for (int i = j; i < (int) a.size(); i++) {
cnt[a[i]]--;
if (cnt[a[i]] == 0) {
merge(a[i], a[i] + 1);
int it = get(a[i]);
if (it != N - 1) {
if (mn[it] == 0) {
prv[it] = -1;
} else {
prv[it] = mn[it] - 1;
}
}
}
}
while ((int) a.size() > j) {
a.pop_back();
}
}
cout << ans << '\n';
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t = 1;
// cin >> t;
while (t--) {
solve();
}
}
