#include <iostream>
#include <cstring>
#include <algorithm>
#include <unordered_set>

using namespace std;

int get(string s, int b)  
{
    int res = 0;
    for (auto c: s)
        res = res * b + c - '0';
    return res;
}

int main()
{
    string a, b;
    cin >> a >> b;

    unordered_set<int> S;

    for (auto& c: a)
    {
        c ^= 1;
        S.insert(get(a, 2));
        c ^= 1;
    }

    for (auto& c: b)
    {
        char t = c;
        for (int i = 0; i < 3; i ++ )
            if (i + '0' != t)
            {
                c = i + '0';
                int x = get(b, 3);
                if (S.count(x))
                {
                    cout << x << endl;
                    return 0;
                }
            }
        c = t;
    }

    return 0;
}