MAKESTR HSGVinh Phuc L9 2015-2016

#define task "MAKESTR"

#include <iostream>
#include <cstdio>
#include <algorithm>

using namespace std;

using ll = long long;
using ld = long double;

constexpr int N = 1e5 + 5;
int n, a[N], b[N];

void Read()
{
    cin >> n;

    for (int i = 1; i <= n; ++i)
        cin >> a[i];
}

void Solve()
{
    sort(a + 1, a + n + 1);

    for (int i = n; i; --i)
    {
        if (a[i] == 0)
        {
            for (int j = 1; j <= i; ++j)
                b[j] = 0;
            break;
        }
        if (i == 1)
        {
            b[i] = a[i];
            break;
        }

        b[i] = a[i];

        for (int j = 1; j < i; ++j)
            a[j] = min(a[j], a[i] - 1);
    }

    ll ans(0);

    for (int i = 1; i <= n; ++i)
        ans += b[i];

    cout << ans;
}

int32_t main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    if (fopen(task ".INP", "r"))
    {
        freopen(task ".INP", "r", stdin);
        freopen(task ".OUT", "w", stdout);
    }

    Read();
    Solve();
}