#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define all(A) A.begin(),A.end()
using vll = vector<ll>;
#define rep(i, n) for (long long i = 0; i < (long long)(n); i++)
ll gcd(ll(a), ll(b)) {
	ll c = a;
	while (a % b != 0) {
		c = a % b;
		a = b;
		b = c;
	}
	return b;
}

vll dx = { 1,-1,0 };
vll dy = { 1,-1,0 };
int main() {
    ll N;
    cin>>N;
    vll A(N);
    rep(i,N)cin>>A[i];
    sort(all(A));
    ll S=0;
    rep(i,N-1){
        if(A[i]+1!=A[i+1]){
            S+=A[i+1];
        }
    }
    cout<<S+A[0]<<endl;

}