#include <bits/stdc++.h>
//#include <atcoder/all>
using namespace std;
//using namespace atcoder;
//using mint = modint1000000007;
//const int mod = 1000000007;
//using mint = modint998244353;
//const int mod = 998244353;
//const int INF = 1e9;
//const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n-1); i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define endl "\n"
#define P pair<int,int>
template<typename A, typename B> inline bool chmax(A& a, const B& b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A& a, const B& b) { if (a > b) { a = b; return true; } return false; }
bool chk(string s, string t) {
	if (s.size() < t.size())return false;
	rep(i,t.size()) {
		if (s[i] != t[i])return false;
	}
	return true;
}
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	string s; cin >> s;
	string ans;
	rep(i, s.size()) {
		string str = s.substr(0, i + 1);
		string rstr = str;
		reverse(all(rstr));
		string s0 = str + rstr;
		str.pop_back();
		string s1 = str + rstr;
		if (chk(s0, s)) {
			if (ans.empty())ans = s0;
			else if (ans.size() > s0.size())ans = s0;
		}
		if (chk(s1, s)) {
			if (ans.empty())ans = s1;
			else if (ans.size() > s1.size())ans = s1;
		}
	}
	cout << ans << endl;
	return 0;
}