package chelper;

import io.InputReader;
import io.OutputWriter;
import misc.SimpleSavingChelperSolution;


public class A extends SimpleSavingChelperSolution {

  public void solve(int testNumber, InputReader in, OutputWriter out) {
    wrapSolve(testNumber, in, out);
  }

  @Override
  public void solve(int testNumber) {
    int n = in.nextInt();
    int m = in.nextInt();
    int[] a = in.nextIntArray(n);
    int[] b = in.nextIntArray(m);

    for (int i = 1; i < 1000; i++) {
      String s = Integer.toString(i);

      boolean ok1 = false;
      for (int j : a) {
        ok1 |= s.contains(Integer.toString(j));
      }

      boolean ok2 = false;
      for (int j : b) {
        ok2 |= s.contains(Integer.toString(j));
      }

      if (ok1 && ok2) {
        out.println(i);
        break;
      }
    }
  }
}