#include <iostream>
#include <cstring>
using namespace std;
int main()
{
    char s[101], x[10][101];
    int counter = 0;
    cin.getline(s, 101);
    char *p = strtok(s, " ");
    while(p != NULL)
    {
        bool ok = true;
        for(int i = 0, j = strlen(p)-1; i< j && ok == 1; i++, j--)
        {
            if(p[i] != p[j])
                ok = false;
        }
        if(ok == true)
            strcpy(x[++counter], p);
        p = strtok(NULL, " ");
    }
    for(int i = 1; i<counter; i++)
        for(int j = i + 1; j<=counter; j++)
            if(strcmp(x[i], x[j]) < 0)
            {
                char c[101];
                strcpy(c, x[i]);
                strcpy(x[i], x[j]);
                strcpy(x[j], c);
            }
    for(int i = 1; i<=counter; i++)
        cout << x[i] <<' ';
}