#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  cin >> a >> b;
  if (a - b == 0)
    cout << a << 6 << " " << b << 7;
  else if (a - b == -1)
    cout << a << 9 << " " << b << 0;
  else if (a == 9 && b == 1)
    cout << 9 << " " << 10;
  else
    cout << -1;
  return 0;
}
