#include<bits/stdc++.h>
using namespace std;using ld=long double;using ll=long long;
using pll=pair<ll,ll>;
const int M=998244353,inv2=(M+1)/2,P=20;const ld eps=1e-8,pi=acos(-1);
ll poww(ll bs,ll x){ll res=1;for(;x;x>>=1,(bs*=bs)%=M)if(x&1)(res*=bs)%=M;return res;}
ll invv(ll bs){return poww(bs,M-2);}
struct S
{
    int n,k,B;vector<int>a,res;
    vector<int>Cl,Cc;int l,c;
    void ini(string&A,string&B)
    {
        l=A.length();c=B.length();int l2=0,c2=0;vector<int>vl,vc;
        Cl.resize(l,c&1),Cc.resize(c,l&1);
        for(int i=0;i<l;i++)
        {
            Cl[i]^=(A[i]=='1');
            if(Cl[i])l2++,vl.push_back(i);
        }
        for(int i=0;i<c;i++)
        {
            Cc[i]^=(B[i]=='1');
            if(Cc[i])c2++,vc.push_back(i);
        }
        if(abs(l2-c2)&1){cout<<"-1\n";return;}
        vector<vector<int>>res(l,vector<int>(c,1));
        if(l2||c2)
        {
            if(!l2&&c2)
            {
                l2++;vl.push_back(0);
            }
            else if(!c2&&l2)
            {
                c2++;vc.push_back(0);
            }
            for(int i=0;i<max(l2,c2);i++)
            {
                int a=vl[min(i,l2-1)],b=vc[min(i,c2-1)];
                res[a][b]=0;
            }
        }
        for(int i=0;i<l;i++,cout<<'\n')for(int j=0;j<c;j++)cout<<res[i][j];
    }
    void solve()
    {

    }
};
signed main()
{
    cout<<fixed<<setprecision(12);
    ios::sync_with_stdio(0);
    cin.tie(0);
    int t=1;//cin>>t;
    string A,B;
    while(cin>>A>>B)
    {S SS;SS.ini(A,B);SS.solve();}
}
/*
1274368 996265816
1807139^
1274369 996265816
1165429^
1274369 996269373
inf^
 */