#include <bits/stdc++.h>
int dx[] = {0, 0, 1, -1, -1, -1, 1, 1};
int dy[] = {1, -1, 0, 0, -1, 1, 1, -1};
template <class T>
inline T biton(T n, T pos) {
  return n | ((T)1 << pos);
}
template <class T>
inline T bitoff(T n, T pos) {
  return n & ~((T)1 << pos);
}
template <class T>
inline T ison(T n, T pos) {
  return (bool)(n & ((T)1 << pos));
}
template <class T>
inline T gcd(T a, T b) {
  while (b) {
    a = a % b;
    swap(a, b);
  }
  return a;
}
template <class T>
inline T bigmod(T p, T e, T m) {
  T ret = 1;
  for (; e > 0; e >>= 1) {
    if (e & 1) ret = (ret * p) % m;
    p = (p * p) % m;
  }
  return (T)ret;
}
using namespace std;
void solve() {
  int n;
  cin >> n;
  vector<int> items;
  for (int i = 0; i < n; i++) {
    int item;
    cin >> item;
    items.push_back(item);
  }
  sort(items.rbegin(), items.rend());
  set<long long> st;
  long long cnt = 0;
  for (int i = n - 1; i >= 0; i--) {
    while (items[i]) {
      if (st.count(items[i]) == 0) {
        cnt += items[i];
        st.insert(items[i]);
        break;
      }
      items[i]--;
    }
  }
  cout << cnt << endl;
}
int main() {
  ios_base::sync_with_stdio(false);
  cout.setf(ios::fixed);
  cout.precision(10);
  cout.tie(nullptr);
  cin.tie(nullptr);
  int t = 1;
  while (t--) {
    solve();
  }
  int pause;
  cin >> pause;
  return 0;
}
