#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cstdio>
#include <cstring>
#include <ctime>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <sstream>
#include <utility>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pii;
#define all(c) (c).begin(), (c).end()
#define loop(i,a,b) for(ll i=a; i<ll(b); i++)
#define rep(i,b) loop(i,0,b)
#define each(e,c) for(auto&e:c)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define mt make_tuple
#define lb lower_bound
#define ub upper_bound
#ifdef DEBUG
#define dump(...) (cerr<<#__VA_ARGS__<<" = "<<(DUMP(),__VA_ARGS__).str()<<" ["<<__LINE__<<"]"<<endl)
struct DUMP:ostringstream{template<class T>DUMP &operator,(const T&t){if(this->tellp())*this<<", ";*this<<t;return *this;}};
#else
#define dump(...)
#endif

#include <set>

typedef vector<string> vs;

bool ok(string s){
    rep(i,s.size()/2) if(s[i]!=s[s.size()-1-i]) return false;
    return true;
}

int main(){
    string line;
    while(getline(cin,line)){
        string s;
        for(char c : line) if(isalpha(c)) s += toupper(c);
        vs cand;
        int n=s.size();
        for(int i=n;i>=3;i--){
            rep(j,n-i+1){
                if(ok(s.substr(j,i))) cand.eb(s.begin()+j, s.begin()+j+i);
            }
        }
        bool used[1111]={};
        rep(j,cand.size()){
            rep(i,j){
                int diff=abs((int)cand[j].size()-(int)cand[i].size());
                diff/=2;
                if(cand[i].size()<cand[j].size()){
                    if(cand[j].substr(diff,cand[i].size())==cand[i]) used[i]=true;
                }
                else{
                    if(cand[i].substr(diff,cand[j].size())==cand[j]){
                        used[j]=true;
                    }
                }
            }
        }
        vs ans;
        rep(i,cand.size()) if(!used[i]) ans.eb(cand[i]);
        rep(i,ans.size()){
            cout << ans[i];
            if(i+1!=(int)ans.size()) cout << " ";
        }
        cout << endl;
    }
}