a,b=map(int,input().split())
print(a*10+2,b*10+3) if a==b else print(a,b) if a<b and b-a==1 else print(99,100) if a==9 and b==1 else print(-1)
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<stdio.h>
#include<cmath>
#include<algorithm>
#include<set>
#include<stack>
#include<deque>
#define all(a) sort(a.begin(),a.end());
using namespace std;
int main()
{
long long a, b;
cin >> a >> b;
if (a == b)
cout << a << 12 << " " << b << 13;
else
{
if (a < b && b - a == 1)
cout << a << 99 << " " << b * 100;
else if (a == 9 && b == 1)
cout << 9 << " " << 10;
else
cout << -1;
}
return 0;
}
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