#include <iostream>
#include <fstream>
#include <string.h>
using namespace std;
ifstream f("ordine.in");
ofstream g("ordine.out");
char s[1000005]; int fr[30],n;
void read(){f.getline(s+1,1000000); n=strlen(s+1); for(int i=1;i<=n;i++)fr[s[i]-'a']++;}
int verif(int x){for(int i=0;i<26;i++)if(fr[i]>(x+1)/2)return 0;return 1;}
void solve()
{
    int i,j;
    for(i=1;i<=n;i++)
        for(j=0;j<26;j++)
           if(fr[j]>0&&s[i-1]!=j+'a'){fr[j]--; if(verif(n-i)){s[i]=j+'a'; break; }else fr[j]++;}
    g<<(s+1);
}
int main()
{
    read(); solve();
    return 0;
}