#include <iostream>
#include <set>
#include <vector>
#include <algorithm>

using namespace std;

int main() {
    int N;
    cin >> N;

    vector<int> sequence(N);
    for (int i = 0; i < N; ++i) {
        cin >> sequence[i];
    }

    // Sort the sequence in descending order to handle larger numbers first
    sort(sequence.rbegin(), sequence.rend());

    set<int> uniqueNumbers;
    int operations = 0;

    for (int i = 0; i < N; ++i) {
        while (sequence[i] > 0 && !uniqueNumbers.insert(sequence[i]).second) {
            // Decrement the number and increase the operation count
            sequence[i]--;
            operations++;
        }
    }

    cout << operations << endl;

    return 0;
}