#include <bits/stdc++.h>
using namespace std;
#define mp make_pair
#define pb push_back
typedef long long ll;
int main()
{
ios_base::sync_with_stdio(false);cin.tie(0); cout.tie(0);
int n;
cin>>n;
long long a[n],c=1;
for(int i=0;i<n;i++) cin>>a[i];
sort(a,a+n);
for(int i=1;i<n-1;i++){
int f1=0,f2=0;
if(a[i]==a[i-1] && a[i]!=1){ a[i-1]-=1; f1+=1; }
if(a[i]==a[i+1]){ a[i+1]+=1; f2+=2; }
i+=f2;
}
set<long long > s;
for(int i=0;i<n;i++) s.insert(a[i]);
cout<<s.size();
return 0;
}
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