#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("Yes");}else{puts("No");}
#define MAX_N 200005

int main() {
    string s;
    cin >> s;
    int n = s.size();
    int f[n];
    rep(i,n)f[i] = s[i] - '0';

    int ans = 0;

    int a[n];
    rep(i,n){
        a[i] = i % 3;
    }

    do{
        int tmp = 0;
        rep(i,n/3){
            int c[3];
            int cnt = 0;
            rep(j,n){
                if(a[j] == i){
                    c[cnt] = f[j];
                }
            }
            if(c[0] != c[1] && c[0] != 0 && c[1] == c[2]){
                tmp += c[0] * 100 + c[1] * 10 + c[2];
            }
        }

        ans = max(ans, tmp);
    }while(next_permutation(a,a+n));

    cout << ans << endl;
    return 0;
}