Problem:
Score : 200 points

Problem Statement

You are given a string S consisting of lowercase English letters. Determine whether all the characters in S are different.

Constraints

2 ≤ |S| ≤ 26, where |S| denotes the length of S.

S consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:

S

Output

If all the characters in S are different, print yes (case-sensitive); otherwise, print no.

Sample Input 1

uncopyrightable

Sample Output 1

yes

Sample Input 2

different

Sample Output 2

no

Sample Input 3

no

Sample Output 3

yes

Solution in C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
int main(void)
{
	char s[26];
	int cnt[26] = {0};
	int i;
	scanf("%s", s);
	i = 0;
	while (s[i] != '\0') {
		// printf("%c", s[i]);
		cnt[s[i++] - 'a']++;
	}
	// putchar('\n');
	// for (i = 0; i < 26; i++)
	// 	printf("%c : %d\n", 'a' + i, cnt[i]);
	i = 0;
	while (cnt[i++] <= 1);
	if (i <= 26)
		puts("no");
	else
		puts("yes");
	return 0;
}