#include <bits/stdc++.h>

using namespace std;

int main()
{
    for (string str; cin >> str; ) {
        vector<int> used(10, 0);
        int digit = -1, theMin = 0x3f3f3f3f;
        for (auto it = str.begin(); it != str.end(); ++it)
            ++used[*it - '0'];
        for (int i = 1; i < 10; i++)
            if (theMin > used[i])
                theMin = used[i], digit = i;
        if (used[0] + 1 <= theMin)
            cout << "1" + string(used[0] + 1, '0') << endl;
        else
            cout << string(theMin + 1, digit + '0') << endl;
    }
    return 0;
}

第二题16行写错了，已经改正过来了，上面是正确代码