#include<bits/stdc++.h>

using namespace std;

map<long long,long long> mp;
map<long long,long long> fl;
map<long long,long long> ex;

long long f(long long x){
  if(ex[x]==0){return 0;}
  if(fl[x]==1){return mp[x];}
  fl[x]=1;
  mp[x]=1+f(x+2);
  return mp[x];
}

int main(){
  int n;
  cin >> n;
  vector<int> vc(n);
  for(int i=0;i<n;i++){cin >> vc[i];ex[vc[i]]=1;}
  sort(vc.begin(),vc.end());
  long long res=n;
  for(int i=0;i<n;i++){
    res+=f(vc[i]+1);
  }
  cout << res << '\n';
}