#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<(to);x++)
#define FORR(x,arr) for(auto& x:arr)
#define FORR2(x,y,arr) for(auto& [x,y]:arr)
#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
//-------------------------------------------------------


int N;
ll A[202020];
vector<ll> R[2];
void solve() {
	int i,j,k,l,r,x,y; string s;
	cin>>N;
	FOR(i,N) cin>>A[i];
	sort(A,A+N);
	FOR(i,N) R[A[i]%2].push_back(A[i]);
	
	ll ret=N;
	ll C[2]={},D[2]={};
	FOR(i,N) {
		x=A[i]%2;
		if(i&&A[i]==A[i-1]+1) {
			C[x]=max(C[x],D[x]+1);
			while(C[x]<R[x].size()&&R[x][C[x]]==R[x][C[x]-1]+2) C[x]++;
			ret+=C[x]-D[x];
		}
		D[x]++;
	}
	
	
	
	cout<<ret<<endl;
	
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false), cin.tie(0);
	FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	cout.tie(0); solve(); return 0;
}