#include <bits/stdc++.h>
using namespace std;

#define rep(i, a, b) for(int i = (a); i < (b); ++i)
#define trav(a, x) for(auto& a : x)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
#define pb push_back
#define fst first
#define snd second

typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> pii;
typedef vector<ll> vi;
typedef vector<vi> vvi;
typedef vector<pii> vii;

int main() {
  cin.sync_with_stdio(0); cin.tie(0);
  cin.exceptions(cin.failbit);

  int n;
  cin >> n;

  vi a(n);
  rep(i,0,n) cin >> a[i];

  multiset<int> arr;
  rep(i,0,n) {
    auto it= arr.lower_bound(a[i]);
    if (it != arr.end() and *it == a[i]) {
      arr.erase(it);
    }
    arr.insert(a[i]-1);
  }

  cout << sz(arr) << endl;
}