// template version 1.14
using namespace std;
#include <bits/stdc++.h>

// varibable settings
#define int long long
const int INF=1e18;
const int MOD=1e9+7;

// define basic macro {{{
#define _overload3(_1,_2,_3,name,...) name
#define _rep(i,n) repi(i,0,n)
#define repi(i,a,b) for(int i=(int)(a);i<(int)(b);++i)
#define rep(...) _overload3(__VA_ARGS__,repi,_rep,)(__VA_ARGS__)
#define _rrep(i,n) rrepi(i,0,n)
#define rrepi(i,a,b) for(int i=(int)((b)-1);i>=(int)(a);--i)
#define rrep(...) _overload3(__VA_ARGS__,rrepi,_rrep,)(__VA_ARGS__)
#define each(i,a) for (auto&& i : a)
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define pb(a) push_back(a)
#define mp(a, b) make_pair(a, b)
#define mt(a, b, c) make_tuple(a, b, c)
#define ceil(a,b) ((a)+(b)-1)/(b)
#define is_in(x, a, b) ((a)<=(x) && (x)<(b))
#define uni(x) sort(all(x));x.erase(unique(all(x)),x.end())
#define ub upper_bound
#define lb lower_bound
#define posl(A, x) (lower_bound(all(A), x)-A.begin())
#define posu(A, x) (upper_bound(all(A),x)-A.begin())
template<class T> inline void chmax(T &a, const T &b) { if((a) < (b)) (a) = (b); }
template<class T> inline void chmin(T &a, const T &b) { if((a) > (b)) (a) = (b); }

typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef long double ld;
typedef pair<int,int> pii;
typedef tuple<int,int,int> iii;

template<typename T> using PQ = priority_queue<T, vector<T>, greater<T>>;
struct Fast { Fast(){ std::cin.tie(0); ios::sync_with_stdio(false); } } fast;

#if defined(PCM) || defined(LOCAL)
  #include "lib/dump.hpp"
#else
  #define dump(...) 42
  #define dump_1d(...) 42
  #define dump_2d(...) 42
#endif
//}}}

signed main() {
  int n;cin>>n;
  vector<int> p(n);
  rep(i, n) {
    cin>>p[i];
  }
  dump(p);

  string ans = "";
  int k = 0;
  int m = 0;
  multiset<int> st;
  rep(i, 0, n+1) st.insert(i);
  rep(i, n){
    while (k<p[i]){
      ans+="(";
      m++;

      k = m;
    }
    if (k>p[i]){
      cout << ":(" << endl;
      return 0;
    }
    ans += ")";
    auto it = st.find(p[i]);
    it = st.erase(it);
    k = *(prev(it));
  }
  dump(ans);

  int lev = 0;
  rep(i, sz(ans)){
    if (ans[i]=='(') lev++;
    if (ans[i]==')') lev--;
    if (lev<0){
      cout << ":(" << endl;
      return 0;
    }
  }
  if (lev==0){
    cout << ans << endl;
  }
  else{
    assert(false);
    cout << ":(" << endl;
  }

  return 0;
}

