#include <iostream>
#include <vector>
#include <map>
#include <cassert>
#include <set>
#include <algorithm>
#define FOR(i, a, b) for(int i = a; i < (int) b; i++)
#define F0R(i, a) FOR (i, 0, a)
#define ROF(i, a, b) for(int i = a; i >= (int) b; i--)
#define R0F(i, a) ROF(i, a, 0)
#define GO(i, a) for (auto i : a)
#define eb emplace_back
#define sz(x) (int) x.size()
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define f first
#define s second
using namespace std;
typedef long long i64;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<pii> vpii;
typedef vector<vi> vvi;
typedef vector<vpii> vvpii;
typedef vector<i64> vi64;
const int dr[] = {+1, -1, +0, +0, +1, -1, -1, +1};
const int dc[] = {+0, +0, +1, -1, +1, -1, +1, -1};
/*
const int dc[] = {+2, +2, -2, -2, +1, -1, +1, -1};
const int dr[] = {+1, -1, +1, -1, +2, +2, -2, -2};
*/
//const int m[] = {+31, +29, +31, +30, +31, +30, +31, +31, +30, +31, +30, +31};
multiset<int> can_remove;
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
int res = 0;
int n;
cin >> n;
F0R (i, n) {
int foo;
cin >> foo;
if (can_remove.find(foo) != can_remove.end()) {
can_remove.erase(can_remove.lower_bound(foo));
} else {
++res;
}
can_remove.insert(foo - 1);
}
cout << res << '\n';
return 0;
}
