#include <bits/stdc++.h>
using namespace std;
using uint = unsigned int;
using ll = long long;
using ull = unsigned long long;
using pii = pair<int, int>;
using pll = pair<long long, long long>;
template <class T> using vec = vector<T>;
template <class T> using vvec = vector<vector<T>>;
#define rep(i, n) for (int i = 0; i < (n); i++)
#define rrep(i, n) for (int i = int(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
constexpr char ln = '\n';
template <class Container> inline int SZ(const Container& v) { return int(v.size()); }
template <class T> inline void UNIQUE(vector<T>& v) { v.erase(unique(v.begin(), v.end()), v.end()); }
template <class T1, class T2> inline bool chmax(T1& a, T2 b) { if (a < b) { a = b; return true; } return false; }
template <class T1, class T2> inline bool chmin(T1& a, T2 b) { if (a > b) { a = b; return true; } return false; }
inline int topbit(ull x) { return x == 0 ? -1 : 63 - __builtin_clzll(x); }
inline int botbit(ull x) { return x == 0 ? 64 : __builtin_ctzll(x); }
inline int popcount(ull x) { return __builtin_popcountll(x); }
inline int kthbit(ull x, int k) { return (x >> k) & 1; }
inline constexpr long long TEN(int x) { return x == 0 ? 1 : TEN(x - 1) * 10; }
const string YESNO[2] = {"NO", "YES"};
const string YesNo[2] = {"No", "Yes"};
inline void YES(bool t = true) { cout << YESNO[t] << "\n"; }
inline void Yes(bool t = true) { cout << YesNo[t] << "\n"; }
template <class T> inline void drop(T x) { cout << x << "\n"; exit(0); }
inline void print() { cout << "\n"; }
template <class T> inline void print(const vector<T>& v) { for (auto it = v.begin(); it != v.end(); ++it) { if (it != v.begin()) { cout << " "; } cout << *it; } print(); }
template <class T, class... Args> inline void print(const T& x, const Args& ... args) { cout << x << " "; print(args...); }
#ifdef MINATO_LOCAL
template <class T1, class T2> ostream& operator<<(ostream& os, pair<T1, T2> p) { return os << "(" << p.first << ", " << p.second << ")"; }
template <size_t N, class TUPLE> void debug_tuple(ostream& os, TUPLE _) { (void)os; (void)_; }
template <size_t N, class TUPLE, class T, class ...Args> void debug_tuple(ostream &os, TUPLE t) { os << (N == 0 ? "" : ", ") << get<N>(t); debug_tuple<N + 1, TUPLE, Args...>(os, t); }
template <class ...Args> ostream& operator<<(ostream& os, tuple<Args...> t) { os << "("; debug_tuple<0, tuple<Args...>, Args...>(os, t); return os << ")"; }
string debug_delim(int& i) { return i++ == 0 ? "" : ", "; }
#define debug_embrace(x) { int i = 0; os << "{";  { x } return os << "}"; }
template <class T> ostream& operator<<(ostream& os, vector<T> v) { debug_embrace( for (T e : v) { os << debug_delim(i) << e; } ) }
template <class T, size_t N> ostream& operator<<(ostream& os, array<T, N> a) { debug_embrace( for (T e : a) { os << debug_delim(i) << e; } ) }
template <class T, size_t N> enable_if_t<!is_same_v<char, remove_cv_t<T>>, ostream>& operator<<(ostream& os, T(&a)[N]) { debug_embrace( for (T e : a) { os << debug_delim(i) << e; } ) }
template <class Key> ostream& operator<<(ostream& os, set<Key> s) { debug_embrace( for (Key e : s) { os << debug_delim(i) << e; }) }
template <class Key, class T> ostream& operator<<(ostream& os, map<Key, T> mp) { debug_embrace( for (auto e : mp) { os << debug_delim(i) << e; }) }
template <class Key> ostream& operator<<(ostream& os, multiset<Key> s) { debug_embrace( for (Key e : s) { os << debug_delim(i) << e; }) }
template <class T> ostream& operator<<(ostream& os, queue<T> q) { debug_embrace( for (; !q.empty(); q.pop()) { os << debug_delim(i) << q.front(); } ) }
template <class T> ostream& operator<<(ostream& os, deque<T> q) { debug_embrace( for (T e : q) { os << debug_delim(i) << e; } ) }
template <class T> ostream& operator<<(ostream& os, priority_queue<T> q) { debug_embrace( for (; !q.empty(); q.pop()) { os << debug_delim(i) << q.top(); } ) }
template <class T> ostream& operator<<(ostream& os, priority_queue<T, vector<T>, greater<T>> q) { debug_embrace( for (; !q.empty(); q.pop()) { os << debug_delim(i) << q.top(); } ) }
void debug_out() { cerr << endl; }
template <class T, class... Args> void debug_out(const T& x, const Args& ... args) { cerr << " " << x; debug_out(args...); }
#define debug(...) cerr << __LINE__ << " : [" << #__VA_ARGS__ << "] =", debug_out(__VA_ARGS__)
#else
#define debug(...) (void(0))
#endif
struct fast_ios { fast_ios() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); cerr << fixed << setprecision(7); }; } fast_ios_;
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

int dp[2][2][2];
int nex[2][2][2];
int main() {
    int N; cin >> N;
    string S,T; cin >> S >> T;
    if (N <= 2) {
        int A = 0, B = 0;
        rep(i,N) {
            A = A* 2 + S[i] - '0';
            B = B * 2 + T[i] - '0';
        }

        int ans = 0;
        for (int l = A; l <= B; l++) {
            for (int r = l; r <= B; r++) {
                int tmp = 0;
                for (int x = l; x <= r; x++) {
                    tmp ^= x;
                }
                chmax(ans,tmp);
            }
        }
        string str = "";
        rep(i,N) {
            str += char('0'+ans%2);
            ans /= 2;
        }
        reverse(all(str));
        cout << str << ln;
        return 0;
    }

    if (S.substr(0,N-2) == T.substr(0,N-2)) {
        int A = 0, B = 0;
        for (int i = N-2; i < N; i++) {
            A = A * 2 + S[i] - '0';
            B = B * 2 + T[i] - '0';
        }

        int ans = 0;
        for (int l = A; l <= B; l++) {
            for (int r = l; r <= B; r++) {
                if ((r-l+1)%2==0) continue;
                int tmp = 0;
                for (int x = l; x <= r; x++) {
                    tmp ^= x;
                }
                chmax(ans,tmp);
            }
        }
        string str = S.substr(0,N-2);
        rep(i,2) {
            str += char('0'+ans%2);
            ans /= 2;
        }
        swap(str[N-1],str[N-2]);
        cout << str << ln;
        return 0;
    }


    string ans = "";
    dp[0][0][0] = 1;
    rep(i,N-2) {
        rep(a,2) rep(b,2) rep(c,2) nex[a][b][c] = 0;
        int s = S[i] - '0';
        int t = T[i] - '0';
        bool check = false;
        rep(j,2) {
            rep(k,2) {
                rep(l,2) {
                    if (!dp[j][k][l]) continue;
                    rep(ns,2) {
                        if (j == 0 and s == 1 and ns == 0) continue;
                        rep(nt,2) {
                            if (k == 0 and t == 0 and nt == 1) continue;
                            if (l == 0 and ns == 1 and nt == 0) continue;
                            if (check) {
                                if (ns+nt!=1) continue;
                                int nj = j, nk = k, nl = l;
                                if (s == 0 and ns == 1) nj = 1;
                                if (t == 1 and nt == 0) nk = 1;
                                if (ns == 0 and nt == 1) nl = 1;
                                nex[nj][nk][nl] = 1;
                            } else {
                                if (ns+nt==1) {
                                    check = true;
                                    rep(a,2) rep(b,2) rep(c,2) nex[a][b][c] = 0;
                                    int nj = j, nk = k, nl = l;
                                    if (s == 0 and ns == 1) nj = 1;
                                    if (t == 1 and nt == 0) nk = 1;
                                    if (ns == 0 and nt == 1) nl = 1;
                                    nex[nj][nk][nl] = 1;
                                } else {
                                    int nj = j, nk = k, nl = l;
                                    if (s == 0 and ns == 1) nj = 1;
                                    if (t == 1 and nt == 0) nk = 1;
                                    if (ns == 0 and nt == 1) nl = 1;
                                    nex[nj][nk][nl] = 1;
                                }
                            }
                        }
                    }
                }
            }
        }

        ans += check ? "1" : "0";
        rep(a,2) rep(b,2) rep(c,2) dp[a][b][c] = nex[a][b][c];
    }

    if(chmax(ans,T.substr(0,N-2))) {
        if (T[N-2]=='1') ans += "11";
        else {
            string SS = S;
            int pos = N-1;
            while (SS[pos]=='1') {
                SS[pos] = '0';
                pos--;
            }
            SS[pos] = '1';
            if (SS==T) ans += "00";
            else ans += "01";
        }
    } else {
        ans += "11";
    }
    cout << ans << ln;
}
