#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  long long int n;
  cin >> n;
  long long int ar[n + 1];
  for (long long int i = 0; i < n; i++) cin >> ar[i];
  sort(ar, ar + n, greater<long long int>());
  vector<long long int> v, ans;
  for (long long int i = 0; i < n; i++) {
    v.push_back(ar[i]);
  }
  ans.push_back(v[0]);
  for (long long int i = 1; i < v.size(); i++) {
    long long int p = v[i];
    while (p >= 0) {
      if (find(ans.begin(), ans.end(), p) != ans.end()) {
        p--;
      } else {
        ans.push_back(p);
        break;
      }
    }
  }
  long long int cnt = 0;
  for (long long int i = 0; i < ans.size(); i++) cnt += ans[i];
  cout << cnt << endl;
}
