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

int main() {
  int N, A;
  cin >> N;
  N = 5e6;
  set<int> SE;
  while (cin >> A) SE.insert(A);
  
  vector<bool> B(N + 1, 1);
  B.at(0) = B.at(1) = 0;
  for (long i = 2; i <= N; i++) if (B.at(i)) for (long j = i * i; j <= N; j += i) B.at(j) = 0;
  vector<int> P;
  for (int i = 1; i <= N; i++) if (B.at(i)) P.push_back(i);
  
  vector<int> cnt(10);
  int ans = 0;
  for (int l = 0, r = 0; r < P.size(); r++) {
    int tmp = P.at(r);
    while (tmp) cnt.at(tmp % 10)++, tmp /= 10;
    bool b1 = 0, b2 = 0;
    for (int i = 0; i < 10; i++) {
      if (SE.count(i) && !cnt.at(i)) b1 = 1;
      if (!SE.count(i) && cnt.at(i)) b2 = 1;
    }
    while (b2 && l < r) {
      tmp = P.at(l++);
      while (tmp) cnt.at(tmp % 10)--, tmp /= 10;
      bool b3 = 0;
      for (int i = 0; i < 10; i++) if (!SE.count(i) && cnt.at(i)) b3 = 1;
      if (!b3) b2 = 0;
    }
    if (!b1 && !b2) {
      int mi = ((l - 1 >= 0) ? P.at(l - 1) : 0) + 1;
      int mx = ((r + 1 < P.size()) ? P.at(r + 1) : 5e6 + 1) - 1;
      ans = max(ans, mx - mi);
    }
  }
  cout << ((ans) ? ans : -1) << "\n";
}