#include <bits/stdc++.h>
using namespace std;
template <class T>
inline void remax(T& A, T B) {
  if (A < B) A = B;
}
template <class T>
inline void remin(T& A, T B) {
  if (A > B) A = B;
}
string ToString(long long num) {
  string ret;
  do {
    ret += ((num % 10) + '0');
    num /= 10;
  } while (num);
  reverse(ret.begin(), ret.end());
  return ret;
}
long long ToNumber(string s) {
  long long r = 0, p = 1;
  for (int i = s.size() - 1; i >= 0; --i) r += (s[i] - '0') * p, p *= 10;
  return r;
}
long long Gcd(long long a, long long b) {
  while (a %= b ^= a ^= b ^= a)
    ;
  return b;
}
long long Power(long long base, long long power) {
  long long ret = 1;
  while (power) {
    if (power & 1) ret *= base;
    power >>= 1;
    base *= base;
  }
  return ret;
}
long long PowerMod(long long base, long long power, long long mod) {
  if (!power) return 1;
  if (power & 1) return (base * PowerMod(base, power - 1, mod)) % mod;
  return PowerMod((base * base) % mod, power >> 1, mod);
}
int Log(long long num, long long base) {
  int ret = 0;
  while (num) {
    ++ret;
    num /= base;
  }
  return ret;
}
int Count(long long mask) {
  int ret = 0;
  while (mask) {
    if (mask & 1) ++ret;
    mask >>= 1;
  }
  return ret;
}
inline void run() {
  long long ans = 0;
  int arr[26];
  int n, m;
  scanf("%d", &n);
  for (int i = 0; i < n;) scanf("%d", arr + i++);
  m = n;
  sort(arr, arr + n);
  for (int i = n - 1; ~i && arr[i] > 0; --i) {
    ans += arr[i];
    for (int j = i - 1; ~j; --j)
      if (arr[j] == arr[i]) --arr[j];
  }
  printf("%I64d\n", ans);
}
int main() {
  FILE* input = stdin;
  FILE* output = stdout;
  while (!feof(input)) {
    run();
    break;
  }
  return 0;
}
