#include <fstream>
using namespace std;
ifstream g("nr.in");
ofstream f("nr.out");
int i,d,c[10],n;
int main()
{
    while(g>>n)
    {
        while(n!=0){
        c[n%10]++;
        n=n/10;}
    }
            for(i=9;i>=0;i--)
        {
            for(d=1;d<=c[i];d++)
            f<<i;
        }
    return 0;
}//idk ce ai gresit lol :))