#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>

bool is_delimiter(char t) {
    if (t == ' ' || t == ',' || t == ':' || t == '-' || t == ';' || t == '.') {
        return true;
    }
    return false;
}

int main() {
    char s[101];
    if (fgets(s, 101, stdin) == NULL) {
        perror("Couldn't read string");
        return 1;
    }
    char *words[100];
    int words_count = 0;
    int prev_pos = 0;
    if (is_delimiter(s[0])) {
        prev_pos = 1;
    }

    int pos = 1;
    while (s[pos] != '\0' && s[pos] != '\n') {
        if (is_delimiter(s[pos])) {
            if (!is_delimiter(s[pos - 1])) {
                words[words_count] = calloc(pos - prev_pos + 1, sizeof(char));
                memcpy(words[words_count], &s[prev_pos], pos - prev_pos);
                // printf("|%s|\n", words[words_count]);
                ++words_count;
            }
            prev_pos = pos + 1;
        }
        ++pos;
    }
    if (!is_delimiter(s[pos - 1])) {
        words[words_count] = calloc(pos - prev_pos + 1, sizeof(char));
        memcpy(words[words_count], &s[prev_pos], pos - prev_pos);
        ++words_count;
    }

    for (int i = 0; i < words_count; ++i) {
        int count = 0;
        for (int j = 0; j < words_count; ++j) {
            if (i != j && strcmp(words[i], words[j]) == 0) {
                ++count;
                words[j][0] = '\0';
            }
        }
        if (count && words[i][0] != '\0') {
            printf("%s\n", words[i]);
        }
    }

    for (int j = 0; j < words_count; ++j) {
        free(words[j]);
    }

    return 0;
}