//In The Name of Beauty
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<ll> vll;
#define IB std::ios::sync_with_stdio(0);
#define pb(x) push_back(x);
#define mp(x,y) make_pair(x,y)
#define pll pair<ll,ll>
#define F first
#define S second
ll const MAXN = 1e6 + 8;
ll const INF = 1e12 + 8;
ll const delta = 1000000007;
ll a[MAXN];
vll last[MAXN];
int main()
{
IB;
cin.tie(0);
cout.tie(0);
ll n;
cin >> n;
for(ll i = 1;i <= n;i++)cin >> a[i];
ll ans = 0;
for(ll i = 1;i <= n;i++)
{
ll t = a[i];
if(!last[t + 1].size())
{
ans++;
}
else
{
last[t + 1].pop_back();
}
last[t].pb(i);
}
cout << ans;
return 0;
}
//Written by M_H_H_7
