#include <stdio.h>
#define LEN 100
#define SIZE 100

void main(void)
{
    int i = 0, k = 0, j = 0, s[LEN], s1[LEN][SIZE];
    gets(s);
    while (s[k] != '') {
        if (s[k] != ' ')
        {
            s1[i][j] = s[k];
            k++;
            j++;
        }
        else {
            s1[i][j] = '';
            for (j = 0; s1[i][j] != ''; j++) {
                if (s1[i][j] == s1[i][j + 1]) {
                    printf("%c", s1[i][j]);
                }
            }
            j = 0;
            i++;
        }
    }
    _getch();
}