// ./an-animal-contest-3-p1-monkey-potato.yml #include <bits/stdc++.h> using namespace std; // Defines #define fs first #define sn second #define pb push_back #define eb emplace_back #define mpr make_pair #define mtp make_tuple #define all(x) (x).begin(), (x).end() // Basic type definitions #if __cplusplus == 201703L // CPP17 only things template <typename T> using opt_ref = optional<reference_wrapper<T>>; // for some templates #endif using ll = long long; using ull = unsigned long long; using ld = long double; using pii = pair<int, int>; using pll = pair<long long, long long>; #ifdef __GNUG__ // PBDS order statistic tree #include <ext/pb_ds/assoc_container.hpp> // Common file #include <ext/pb_ds/tree_policy.hpp> using namespace __gnu_pbds; template <typename T, class comp = less<T>> using os_tree = tree<T, null_type, comp, rb_tree_tag, tree_order_statistics_node_update>; template <typename K, typename V, class comp = less<K>> using treemap = tree<K, V, comp, rb_tree_tag, tree_order_statistics_node_update>; // HashSet #include <ext/pb_ds/assoc_container.hpp> template <typename T, class Hash> using hashset = gp_hash_table<T, null_type, Hash>; template <typename K, typename V, class Hash> using hashmap = gp_hash_table<K, V, Hash>; const ll RANDOM = chrono::high_resolution_clock::now().time_since_epoch().count(); struct chash { ll operator()(ll x) const { return x ^ RANDOM; } }; #endif // More utilities int SZ(string &v) { return v.length(); } template <typename C> int SZ(C &v) { return v.size(); } template <typename C> void UNIQUE(vector<C> &v) { sort(v.begin(), v.end()); v.resize(unique(v.begin(), v.end()) - v.begin()); } template <typename T, typename U> void maxa(T &a, U b) { a = max(a, b); } template <typename T, typename U> void mina(T &a, U b) { a = min(a, b); } const ll INF = 0x3f3f3f3f, LLINF = 0x3f3f3f3f3f3f3f3f; int K, D, mn = INF; int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cin >> K >> D; bool has0 = false; for (auto i = 0; i < D; i++) { int x; cin >> x; if (x) mina(mn, x); else has0 = true; } if (mn == INF) cout << (-1) << '\n'; else { if (has0) { cout << mn; for (auto i = 0; i < K-2; i++) cout << 0; if (K > 1) cout << mn; cout << '\n'; } else { for (auto i = 0; i < K; i++) cout << (mn); cout << '\n'; } } return 0; }