#include<iostream>
#include<string>
#include<iomanip>
#include<cmath>
#include<vector>
#include<algorithm>
#include<utility>

using namespace std;

#define int long long
#define endl "\n"

constexpr long long INF = (long long)1e18;
constexpr long long MOD = 1'000'000'007; 

struct fast_io {
	fast_io(){
		std::cin.tie(nullptr);
		std::ios::sync_with_stdio(false);
	};
} fio;

signed main(){
	cout<<fixed<<setprecision(10);
	
	string A, B;
	string C;
	
	cin>>A>>B;
	
	C.resize(max(A.size(), B.size()), '0');
	
	for(int i = A.size()-1, j = B.size()-1, k = C.size()-1; k >= 0; i--,j--, k--){
		if(i < 0) C[k] = B[j];
		else if(j < 0) C[k] = A[i];
		else {
			if(A[i] == '1' || A[i] == '0'){
			} else exit(2);
			if(A[i] != B[j]) C[k] = '1';
			else C[k] = '0';
		}
	}
	
	cout<<C<<endl;
	
	
	return 0;
}