#include <bits/stdc++.h>
using namespace std;

using ll = long long;

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  
  int n;
  cin >> n;
  
  set<ll> s;
  for (int i = 0; i < n; i++) {
    ll a;
    cin >> a;
    s.insert(a);
  }
  
  map<ll, ll> mp;
  ll ans = n;
  for (auto &f : s) {
    ll count = 0;
    if (s.find(f - 1) != s.end()) count++;
    if (mp.find(f - 1) != mp.end()) count += mp[f - 1];
    mp[f + 1] = count;
    ans += count;
  }
  
  cout << ans << '\n';
}