#include <bits/stdc++.h>
using namespace std;
// #define int long long
using ll=long long;
using vi=vector<int>;
using vl=vector<long long>;
using pii=pair<int,int>;
using pll=pair<ll,ll>;
#define ITR(v,c) for(auto v=begin(c);v!=end(c);v++)
#define FORE(x,c) for(auto &x:c)
#define FOR(v,a,n) for(int v=a;v<(int)(n);v++)
#define REP(v,n) FOR(v,0,n)
#define RREP(v,n) for(int v=((int)(n)-1);v>=0;v--)
#define ALL(c) begin(c),end(c)
#define RALL(c) rbegin(c),rend(c)
#define SZ(c) ((int)c.size())
const int DX[9]={0,1,0,-1,1,1,-1,-1,0}, DY[9]={-1,0,1,0,-1,1,1,-1,0};
const int INF=1e9; const long long INFLL=1e18;
template<class T> ostream& operator << (ostream &os, const vector<T> &v) {
    ITR(i,v) os<<*i<<(i==end(v)-1?"":"\n"); return os; }
template<class T> istream& operator >> (istream &is, vector<T> &v) {
    ITR(i,v) is>>*i; return is; }
//------------------------------------------------------------------------------

int dp[10000];
inline bool check(int bits,int index) {
    return (bits&(1<<index));
}
int main() {
    string str;
    cin>>str;
    vector<int> a;
    for(char x:str) a.push_back(x-'0');
    int N=str.size();

    int ans=0;
    for(int S=0; S<=(1<<N); S++) {
        for(int i=0; i<N; i++) {
            for(int j=i+1; j<N; j++) {
                for(int k=j+1; k<N; k++) {
                    if(!check(S,i) || !check(S,j) || !check(S,k)) continue;
                    if(a[i]==0 || a[j]!=a[k] || a[i]==a[j]) continue;

                    int t=S^(1<<i)^(1<<j)^(1<<k);
                    dp[S]=max(dp[S],dp[t]+a[i]*100+a[j]*10+a[k]);
                }
            }
        }
        ans=max(ans,dp[S]);
    }
    cout<<ans<<endl;
    return 0;
}