#include<bits/stdc++.h>
using namespace std;
const int N=5e5+10,Base=10597,Mod=1e9+2361; char s[N],S[N]; int p[N],h[N],h2[N];
int get(int l,int r) { return (h[r]-1ll*h[l-1]*p[r-l+1]%Mod+Mod)%Mod; }
int get2(int l,int r) { return (h2[r]-1ll*h2[l-1]*p[r-l+1]%Mod+Mod)%Mod; }
int main() {
    ios::sync_with_stdio(false),cin.tie(nullptr);
    int n; cin>>s,n=strlen(s),p[0]=1;
    for(int i=n;i>=1;i--) s[i]=s[i-1];
    for(int i=1;i<=n;i++) S[i]=s[i],p[i]=1ll*p[i-1]*Base%Mod;
    reverse(s+1,s+n+1);
    for(int i=1;i<=n;i++) h[i]=(1ll*h[i-1]*Base%Mod+s[i])%Mod,h2[i]=(1ll*h2[i-1]*Base%Mod+S[i])%Mod;
    int k=1;
    for(int i=n;i>=2;i--) if((((i&1)&&get(1,i>>1)==get2(n-i+1,n-(i>>1)-1))||((!(i&1))&&get(1,i>>1)==get2(n-i+1,n-(i>>1))))) { k=i; break; }
    for(int i=1;i<=n;i++) cout<<S[i];
    for(int i=n-k;i>=1;i--) cout<<S[i];
    return 0;
}