#define _USE_MATH_DEFINES
#include <sstream> //string stream its useful!
#include<string>
#include<iostream>
#include<utility> //pair
#include <vector> // vector
#include <algorithm>    // swap,sort,binary_search
#include <functional>   // std::greater
#include <map> //map
#include<set> //set
#include<queue> //queue
#include<list> //list
#include<cmath>
#include<numeric>
#include<cassert>
#include <iomanip> //cout<<setprecision

typedef long long ll;
#define ARRAY_LENGTH(array) (sizeof(array) / sizeof(array[0]))

using namespace std;
void omajinai() {
    
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout<<setprecision(15);
    //freopen("txt.csv","r",stdin);
}

int getans(vector<int> v, vector<int> p){
    int sum  = 0;
    for(int i = 0; i<10;i++){
        if(p[i]>=2){
            p[i]-=2;
            int k = p[i];
            for(int j:v){
                if(j != i){
                    if(j==0||p[j]==0) continue;
                    p[j]--;
                    sum = max(sum,getans(v,p) + j*100 + i*11);
                    p[j]++;
                }else{
                    k--;
                    if(k<0) break;
                }
            }
            p[i]+=2;
        }
    }
    return sum;
}

int main(){
    omajinai();
    ll N; cin>>N;
    vector<int> v;
    while(true){
        v.push_back(N%10);
        if(N<10) break;
        N/=10;
    }
    reverse(v.begin(),v.end());
    vector<int> p(10);
    for(int i:v){p[i]++;}
    cout<<getans(v,p)<<endl;
    
    
}