#include <bits/stdc++.h>
using namespace std;
#define ll long long
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
template <class T>
using ordered_set = tree<T, null_type,less<T>, rb_tree_tag,tree_order_statistics_node_update>;
// find_by_order((int)k) returns iterator of the kth element
// order_of_key((T)key) returns the number of elements less than this key
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
int n;
cin >> n;
vector<int> a(n);
for (int& u : a) cin >> u;
map<int, int> st;
for (int i = 0; i < n; i++) st[a[i]] += 1;
a.insert(a.begin(), 0);
auto adjacent = [&](int x, int y) {
if (x == y) return st[x] >= 2;
if (x > y) swap(x, y);
auto iter = st.lower_bound(y);
if (iter == st.begin()) return false;
return prev(iter)->first == x;
};
auto erase_element = [&](int x) {
st[x] -= 1;
if (st[x] == 0) st.erase(x);
};
function<int(int)> solve = [&](int i) {
if (i == 0) return 0;
int j = i;
int cnt = 1;
while (j - 1 >= 1) {
if (a[j - 1] == a[j]) {
if (st[a[j]] >= cnt + 1) {
cnt += 1;
j -= 1;
}
else break;
} else {
if (adjacent(a[j - 1], a[j])) {
cnt = 1;
j -= 1;
} else break;
}
}
for (int k = j; k <= i; k++) erase_element(a[k]);
return 1 + solve(j - 1);
};
cout << solve(n) << "\n";
}
