#include <bits/stdc++.h>
using namespace std;
//#define DEBUG_MODE
#define endl '\n'
#ifdef DEBUG_MODE
#define DEBUG(X) debug_func(X, #X)
#define DEBUG_ENDL endl
#define DEBUG_SEPARATOR_LINE cout<<"=================\n"
#else
#define DEBUG(X) 0
#define DEBUG_ENDL 0
#define DEBUG_SEPARATOR_LINE 0
#endif
#define ALL(V) (V).begin(), (V).end()
#define ALLR(V) (V).rbegin(), (V).rend()
#define DEBUG_ENDL_S(S) ((S).size() ? "\n" : "")
template <typename T> using V = vector<T>;
template <typename T> using VV = V<V<T>>;
template <typename T, typename U> using P = pair<T, U>;
using ll = int64_t;
using PLL = P<ll, ll>;
template <typename T> const T& var_min(const T &t) { return t; }
template <typename T> const T& var_max(const T &t) { return t; }
template <typename Head, typename... Tail> const Head& var_min(const Head &head, const Tail&... tail) { return min(head, var_min(tail...)); }
template <typename Head, typename... Tail> const Head& var_max(const Head &head, const Tail&... tail) { return max(head, var_max(tail...)); }
template <typename T, typename... Tail> void chmin(T &t, const Tail&... tail) { t = var_min(t, tail...); }
template <typename T, typename... Tail> void chmax(T &t, const Tail&... tail) { t = var_max(t, tail...); }
void debug_func_preffix(const string &s) { if(s.size()) cout << s << " = "; }
template <typename T>
void debug_func(const T &t, const string &s = "") {
    debug_func_preffix(s);
    cout << t << DEBUG_ENDL_S(s);
}
template <typename T, typename U>
void debug_func(const P<T, U> &p, const string &s = "") {
    debug_func_preffix(s);
    cout << "(";
    debug_func(p.first);
    cout << ", ";
    debug_func(p.second);
    cout << ")" << DEBUG_ENDL_S(s);
}
template <typename T>
void debug_func(const V<T> &v, const string &s = "") {
    for(ll i = 0; i < v.size(); i++) {
        string t = s + "[" + to_string(i) + "]";
        debug_func(v[i], t);
    }
}

const ll INF = 5e15;

int main() {
    ll N;
    cin >> N;
    V<ll> P(N);
    for(ll &e : P) {
        cin >> e;
        e--;
    }
    {
        auto tmp = P;
        for(ll i = 0; i < N; i++) P[tmp[i]] = i;
    }
    DEBUG(P);
    P.push_back(N);
    string ans;
    V<bool> watched(N + 10, false);
    ll want = 0;
    ll pre = INF;
    bool padded = false;
    for(ll i = 0; i < N; i++) {
        ans += '(';
        watched[P[i]] = true;
        bool added = false;
        for(; watched[want] && want < N; want++) {
            ans += ')';
            added = true;
        }
        if(!added) {
            DEBUG(pre);
            DEBUG(P[i]);
            if(pre < P[i] && !padded) {
                cout << ":(\n";
                return 0;
            }
        }
        pre = P[i];
        DEBUG(ans);
        padded = added;
    }
    cout << (ans.size() == 2 * N ? ans : ":(") << endl;
    return 0;
}

