// #pragma GCC optomize ("Ofast")
// #pragma GCC optomize ("unroll-loops")
// #pragma GCC target ("avx,avx2,fma")
#include <bits/stdc++.h>
#define F first
#define S second
#define ll long long
#define int long long
#define pb push_back
#define all(x) (x.begin(),x.end())
#define ios ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
using namespace std;
const ll N = 1e6+7, INF = 1e18, inf = 1e9 , mod = 998244353;
int a[N];
int c[N];
int pos[N];
unordered_map<int,int>mp;
vector<int>v[N];
signed main(){
ios;
int tt=1;
// cin>>tt;
while(tt--){
int n;
cin>>n;
for(int i=1;i<=n;i++)cin>>a[i];
int cnt=1;
for(int i=1;i<=n;i++){
if(mp[a[i]+1]>0){
c[i]=c[v[a[i]+1][pos[a[i]+1]]];
pos[a[i]+1]++;
mp[a[i]+1]--;
}else c[i]=cnt++;
mp[a[i]]++;
v[a[i]].pb(i);
}
set<int>ans;
for(int i=1;i<=n;i++)ans.insert(c[i]);
cout<<ans.size();
}
}
