#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  cin >> a >> b;
  if (a + 1 == b)
    cout << a << 9 << " " << b << 0;
  else if (a == b)
    cout << a << 1 << " " << b << 2;
  else if (a == 9 && b == 1)
    cout << a << 9 << " " << b << "00";
  else
    cout << -1;
}
