/* Problem URL: https://codeforces.com/contest/915/problem/C */

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;

#define V vector

#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)

#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)

#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()

using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;

using ll = long long;

using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;

template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
    os << vec[0];
    for (size_t i = 1; i < vec.size(); i++) {
        os << ' ' << vec[i];
    }
    os << '\n';
    return os;
}

template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
    for (auto &i : vec) {
        is >> i;
    }
    return is;
}

template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
    for (auto &i : vec) {
        os << i[0];
        for (size_t j = 1; j < i.size(); j++) {
            os << ' ' << i[j];
        }
        os << '\n';
    }
    return os;
}

template<class v>
auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
    for (auto &i : vec) {
        for (auto &j : i) {
            is >> j;
        }
    }
    return is;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    string a, b;
    cin >> a >> b;

    sort(all(a), greater<>());

    if (b.size() > a.size()) {
        cout << a << '\n';
        return 0;
    }

    V<char> maximal(b.size());

    maximal.back() = b.back();

    for (int i = (int)b.size() - 2; i >= 0; i--) {
        maximal[i] = max(maximal[i + 1], b[i]);
    }

    vi count(10);

    repv(i, a) {
        count[i - '0']++;
    }

    function<bool(int, int)> getans = [&](int i, int p) {
        if (i >= a.size()) {
            return a <= b;
        }

        if (p) {
            int now = 0;
            while (count[now] == 0) {
                now++;
            }

            count[now]--;
            a[i] = now + '0';
            bool res = getans(i + 1, 1);
            count[now]++;

            return res;
        }

        int now = 9;

        while (count[now] == 0) {
            now--;
        }

        a[i] = now + '0';
        count[now]--;

        while (!getans(i + 1, 1)) {
            count[now]++;
            now--;

            while (count[now] == 0) {
                now--;
            }

            a[i] = now + '0';
            count[now]--;
        }

        return getans(i + 1, 0);
    };

    getans(0, 0);

    cout << a << '\n';
}