#include <vector>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <algorithm>
#include <utility>
#include <functional>
#include <sstream>
#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <climits>
#include <fstream>
using namespace std;
inline int toInt(string s) { int v; istringstream sin(s); sin >> v; return v; }
template<class T> inline string toStr(T x) { ostringstream sout; sout << x; return sout.str(); }
typedef vector<int> vi;
typedef vector<vi>  vvi;
typedef vector<string> vs;
typedef pair<int, int> pii;
typedef long long ll;
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
#define REP(i,n) FOR(i,0,(n)-1)
const double EPS = 1e-10;
const double PI = acos(-1.0);
const int INF = INT_MAX / 10;

typedef pair<string, int> psi;

int main() {
	string ss;
	cin >> ss;
	int l = ss.length();
	
	int ans = 0;
	queue<psi> Q;
	Q.push(psi(ss, 0));
	while (!Q.empty()) {
		psi p = Q.front();
		Q.pop();
		ans = max(ans, p.second);
		string s = p.first;

		REP(i, l) {
			if (s[i] != 'x' && s[i] != '0') {
				FOR(j, i + 1, l - 1) {
					if (s[j] != 'x' && s[i] != s[j]) {
						FOR(k, j + 1, l - 1) {
							if (s[j] == s[k]) {
								string ns = s;
								ns[i] = ns[j] = ns[k] = 'x';
								int nn = p.second + (s[i] - '0') * 100 + (s[j] - '0') * 10 + (s[k] - '0');
								Q.push(psi(ns, nn));
							}
						}
					}
				}
			}
		}
	}
	
	cout << ans << endl;
	return 0;
}