#include <stdio.h>
#include <string.h>
typedef struct {
char word[600];
int len;
} word;
int main() {
static word word_, wordMax;
static char str[600], *p = str, *q;
gets(str);
for(; *p != 0; p++) {
if(*p != ' ' && *p != '.') {
word_.word[word_.len++] = *p;
} else {
if(wordMax.len < word_.len) {
wordMax.len = word_.len;
strcpy(wordMax.word, word_.word);
}
for(q = word_.word; *q != 0; q++) {
*q = 0;
}
word_.len = 0;
}
}
puts(wordMax.word);
}