#include <iostream>
#include <bitset>

using namespace std;

int main()
{
    bitset<10> exist(0);
    uint32_t n, result = 0u;
    cin >> n;
    while (n > 0)
    {
        auto i = n % 10;
        if (!exist.test(i)) {
            exist.flip(i);
            result = result * 10 + i;
        }
        n /= 10;
    }
    cout << result << endl;
}