#include<iostream>
#include<set>
#include<algorithm>
#include<vector>
#include<string>
#include<set>
#include<map>
#include<numeric>
#include<queue>
#include<cmath>
using namespace std;
typedef long long ll;
const ll INF=1LL<<60;
typedef pair<int,int> P;
typedef pair<int,P> PP;
const ll MOD=998244353;


int main(){
    string A,B;
    cin>>A;
    cin>>B;
    
    while(A.size()>B.size()){
        B='0'+B;
    }
    while(B.size()>A.size()){
        A='0'+A;
    }
    
    //reverse(A.begin(),A.end());
    //reverse(B.begin(),B.end());


    //cout<<"A="<<A<<endl;
    //cout<<"B="<<B<<endl;

    int len=A.size();
    int ans=0;
    for(int i=len-1;i>=0;i--){
        int a=A[i]-'0';
        int b=B[i]-'0';

        int c=((a+b)&1)<<((len-1)-i);
        ans+=c;
    }

    cout<<ans<<endl;

}