#include <bits/stdc++.h>
#define F first
#define S second
#define pb push_back
#define ppb pop_back
#define ep insert
#define endl '\n'
#define elif else if
#define pow pwr
#define sqrt sqrtt
#define int long long
#define ll long long
#define y1 YONE
typedef unsigned long long ull;
using namespace std;
const int N=1e6+5;
int a[N],n,f[N];
int32_t main(){
ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
cin>>n;
for (int i=1;i<=n;i++) cin>>a[i];
int ans=n;
for (int i=n;i;i--){
if (f[a[i]-1]) ans--,f[a[i]-1]--;
f[a[i]]++;
}cout<<ans<<endl;
return 0;
}
