#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  cin >> a >> b;
  if (a + 1 == b)
    cout << a << '9' << endl << b << '0';
  else if (a == 9 && b == 1)
    cout << "9 10";
  else if (a == b)
    cout << a << '1' << endl << b << "2";
  else
    cout << "-1";
}
