#include<bits/stdc++.h>
#define REP(i,n) for(int i=0,i##_len=int(n);i<i##_len;++i)
#define rep(i,a,b) for(int i=int(a);i<int(b);++i)
#define All(x) (x).begin(),(x).end()
#define rAll(x) (x).rbegin(),(x).rend()
using namespace std;
using ll = long long;

int main(){
    string a;
    cin>>a;
    for(int len = a.size(); len <= 2*a.size(); len++) {
        bool ok = true;
        string s;
        s.resize(len);
        REP(idx, (len+1)/2) {
            int bk = len - idx - 1;
            if(bk < a.size() && a[idx] != a[bk]) {
                // cerr << len << " " << idx << " " << bk << " " << a[idx] << " " << a[bk] << endl;
                ok = false;
                break;
            }
            else {
                s[bk] = s[idx] = a[idx];
            }
        }
        if(ok) {
            cerr << "Yes" << endl;
            cout << s << endl;
            break;
        }
    }
}