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


#define MAX_STRINGS 128
#define MAX_STRING_LENGTH 256


void ReadStrings(char **strings, int *nstrings, int maxstrings, FILE *fp)
{
  char string[MAX_STRING_LENGTH];

  *nstrings = 0;
  while (fgets(string, MAX_STRING_LENGTH, fp)) {
    strings[(*nstrings)++] = strdup(string);
    if (*nstrings >= maxstrings) break;
  } 
}


void WriteStrings(char **strings, int nstrings, FILE *fp)
{
  int i;

  for (i = 0; i < nstrings; i++)
    fprintf(fp, "%s", strings[i]);
}


int CompareStrings(char *string1, char *string2)
{
  char *p1 = string1;
  char *p2 = string2;

  while (*p1 && *p2) {
    if (*p1 < *p2) return -1;
    else if (*p1 > *p2) return 1;
    p1++; 
    p2++;
  }

  return 0;
}


void SortStrings(char **strings, int nstrings)
{
  int i, j;

  for (i = 0; i < nstrings; i++) {
    for (j = i+1; j < nstrings; j++) {
      if (CompareStrings(strings[i], strings[j]) > 0) { 
        char *swap = strings[i];
        strings[i] = strings[j];
        strings[j] = swap;
      }
    }
  }
}


int main()
{
  char *strings[MAX_STRINGS];
  int nstrings;

  ReadStrings(strings, &nstrings, MAX_STRINGS, stdin);
  SortStrings(strings, nstrings);
  WriteStrings(strings, nstrings, stdout);

  return 0;
}