#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second
#define repl(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define rep(i,n) repl(i,0,n)
#define each(itr,v) for(auto itr:v)
#define pb(s) push_back(s)
#define mp(a,b) make_pair(a,b)
#define all(x) (x).begin(),(x).end()
#define dbg(x) cout<<#x"="<<x<<endl
#define maxch(x,y) x=max(x,y)
#define minch(x,y) x=min(x,y)
#define uni(x) x.erase(unique(all(x)),x.end())
#define exist(x,y) (find(all(x),y)!=x.end())
#define bcnt(x) bitset<32>(x).count()

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> P;
typedef pair<P, int> PPI;
typedef pair<ll, ll> PL;
typedef pair<P, ll> PPL;

#define INF INT_MAX/3

#define MAX_N 1000

string s;
bool used[22];

int dfs(){
	int c,w;
	int res=0;
	rep(i,s.length()){
		if(!used[i]&&s[i]!='0'){
			c=s[i]-'0';
			used[i]=true;
			repl(j,i+1,s.length())repl(k,j+1,s.length()){
				if(s[i]!=s[j]&&s[j]==s[k]&&!used[j]&&!used[k]){
					used[j]=used[k]=true;
					w=s[j]-'0';
					maxch(res,c*100+w*10+w+dfs());
					used[j]=used[k]=false;
				}
			}
			used[i]=false;
		}
	}
	//dbg(res);
	return res;
}

int main(){
	cin.sync_with_stdio(false);
	memset(used,0,sizeof(used));
	cin>>s;
	cout<<dfs()<<endl;
	return 0;
}