#include<bits/stdc++.h>

using namespace std;

int main()
{
    string s_1, s_2;
    cin>>s_1>>s_2;

    int t1  = s_1.size(), t2 = s_2.size();
    int tam = max(t1, t2);


    for (int i=0; i < (tam - t1) ; i++)
        s_1 = "0"+s_1;
    for (int i=0; i < (tam - t2) ; i++)
        s_2 = "0"+s_2;

      

    
    string res = "";
    for (int i=0; i< tam ;i++)
    {
        if( (s_1[i] <= '2' && s_2[i] <= '2') || (s_1[i] >= '7' && s_2[i] >= '7') )
            res += "0";
        else    
            res += "9";

    }

    cout<<res<<endl;


    return 0;
}