#include <bits/stdc++.h> 
#define repr(i,a,b) for(int i=a;i<b;i++) 
#define rep(i,n) for(int i=0;i<n;i++) 
#define reprrev(i,a,b) for(int i=b-1;i>=a;i--) // [a, b) 
#define reprev(i,n) reprrev(i,0,n) 
#define _GLIBCXX_DEBUG 
#define int long long         
using ll = long long; 
using ull = unsigned long long; 
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; } 
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; } 
const ll mod = 1e9+7; 
void chmod(ll &M){ 
  if(M >= mod) M %= mod; 
  else if(M < 0){ 
     M += (abs(M)/mod + 1)*mod; 
    M %= mod; 
} 
} 

int getl(int i, int N) { return i==0? N-1:i-1; }; 
int getr(int i, int N) { return i==N-1? 0:i+1; }; 
long long GCD(long long a, long long b) { 
  if (b == 0) return a; 
  else return GCD(b, a % b); 
} 
using namespace std; 
using Graph = vector<vector<int>>;

signed main() {
  string A; cin >> A;
  int n = A.length();
  int ind_pa = n-2; 
  int count = 1;
  rep(i, n) {
    int tmp = 0;
    int a = i-1, b = i+1;
    while(a >= 0 && b <= n-1) {
      if(A[a]==A[b]) { 
        tmp++;
        a--; b++;
        }
      else break;
    } 
    cerr << tmp << " " << b << endl;
    if(tmp > count && b == n) {
      cerr << tmp << endl;
      count = tmp;
      ind_pa = a; 
    } 
  }
  if(count == n/2) {
    cout << A << endl;
    return 0;
  }
  string ans = "";
  string A_ = A.substr(0, ind_pa+1);
  string B_ = A.substr(ind_pa+1, count);
  ans += A_; ans += B_;
  reverse(A_.begin(), A_.end());
  ans += A_;
  cout << ans << endl;
  
  
  }