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

int readword (FILE * file, struct stralloc * sa)
{
	int c;
	if (feof (file))
		return 0;
	if (!stralloc_copys (sa, ""))
		return 0;
	while (1) {
		c = fgetc (file);
		if (c < 0)
			break;
		if (isspace (c)) {
			if (!sa->len)
				continue;
			else
				break;
		}
		if (!stralloc_readyplus (sa, 1))
			return 0;
		sa->s[sa->len] = c;
		sa->len++;
	}
	return sa->len;
}


int main (int argc, char ** argv)
{
	stralloc sa = {0};
	stralloc dsts[1+'z'-'a'];
	FILE * file;
	int idx;

	memset (dsts, 0, sizeof (dsts));
	switch (argc) {
	case 1:
		file = stdin;
		break;
	case 2:
		file = fopen (argv[1], "r");
		if (!file) {
			perror ("fopen");
			return 1;
		}
		break;
	default:
		fprintf (stderr, "Too many arguments\n");
		return 1;
	}
	while (readword (file, &sa)) {
		if (!sa.len)
			continue;
		if ((sa.s[0] < 'a') || (sa.s[0] > 'z'))
			continue;
		idx = sa.s[0] - 'a';
		if (dsts[idx].len) {
			if (!stralloc_append (dsts+idx, " "))
				return 1;
		}
		if (!stralloc_cat (dsts+idx, &sa))
			return 1;
	}
	for (idx = 0; idx <= 'z' - 'a'; ++idx) {
		if (!stralloc_0 (dsts+idx))
			return 1;
		printf ("%s\n", dsts[idx].s);
	}
	return 0;
}