#include <bits/stdc++.h>

#define int long long

#define double long double

#define INF (int)(1e18)

#define maxn 1100005

using namespace std;

string s,t;

string ss;

int h[maxn];

signed main() {
	
	ios::sync_with_stdio(0);
	
	cin.tie(0);
	
	cout.tie(0);
	
	cin >> s;
	
	for(auto i : s){
		
		t += '@';
		
		t += i;
		
	}
	
	t += '@';
	
	ss = s;
	
	s = t;
	
	int n = s.length();
	
	int N = ss.length();
	
	for(int i = 0,j = 0;i < n;++ i){
		
		if(i <= j + h[j]){
			
			h[i] = min(h[2 * j - i],j + h[j] - i);
			
		}
		
		while(i - h[i] >= 0 && i + h[i] < n && s[i - h[i]] == s[i + h[i]]) ++ h[i];
		
		if(i + h[i] > j + h[j]) j = i;
		
	}
	
	int ans = INF;
	
//	for(int i = 0;i < n;++ i) cout << h[i] << " \n"[i == n - 1];
	
	for(int i = n - 1;i >= 0;i -= 2){
		
		if(h[i] == n - i){
			
			int cnt = h[i] / 2 * 2;
			
			ans = min(ans,N - cnt);
			
		}
		
	}
	
	for(int i = n - 2;i > 0;i -= 2){
		
		if(h[i] == n - i){
			
			int cnt = h[i] / 2 * 2 - 1;
			
			ans = min(ans,N - cnt);
			
		}
		
	}
	
//	cout << ans << "\n";
	
	cout << ss;
	
	for(int i = ans - 1;i >= 0;-- i) cout << ss[i];
	
	return 0;
	
}
/*

*/