10126.cpp

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<ctype.h>
#define MAXN 20002

char word[MAXN][40];
char str[100000];
int tw, fre;

int com(const void *a, const void *b) {
	return (strcmp( (char *)a, (char *)b));
}

void Sep() {
	int i, j, k;
	char temp[25];
	for(i = 0; str[i]; ) {
		if(!isalpha(str[i])) {
			i++;
			continue;
		}
		k = 0;
		for(j = i; str[j] && isalpha(str[j]); j++) temp[k++] = tolower(str[j]);
		i = j;
		temp[k] = NULL;
		strcpy(word[tw++],temp);
	}
}

void Cal() {
	int i, j, k, f = 1;
	qsort((void *)word,tw,sizeof(word[0]),com);
	for(i = 0; i<tw;) {
		k = 1;
		for(j = i+1;  j<tw && !strcmp(word[i],word[j]); j++) 
			k++;
		i = j;
		if(k == fre) {
			f = 0;
			printf("%s\n",word[i-1]);
		}
	}
	if(f) printf("There is no such word.\n");
}

int main() {
	int k = 0, m = 0;
//	freopen("c:\\zip.in","r",stdin);
//	freopen("c:\\out.txt","w",stdout);
	while(scanf("%s",str) != EOF) {
		fre = atoi(str);
		tw = 0;
		while(1) {
			scanf("%s",str);
			if(!strcmp(str,"EndOfText")) break;
			Sep();
			m++;
		}
		if(k++) printf("\n");
		Cal();
	}
	return 0;

}