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 9.2.1) (judge verdict: Accepted)

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<math.h>
#define rep(i,n) for(int i=0;i<n;i++)
int gcd(int a, int b){
    int r=1;
    while(r!=0){
        r=a%b;
        a=b;
        b=r;
    }
    return a;
}
void revStr(char* str){
    int size = strlen(str);
    int i,j;
    char tmp = {0};
    for(i = 0, j = size - 1; i < size / 2; i++, j--){
        tmp = str[i];
        str[i] = str[j];
        str[j] = tmp;
    }return;
}
typedef struct{
    int a,b,c;
}data;

//昇順
int compare_int(const void *a, const void *b)
{
    return *(int*)a - *(int*)b;
}
//構造体降順
int comp( const void *c1, const void *c2 )
{
  data test1 = *(data *)c1;
  data test2 = *(data *)c2;
  int tmp1 = test1.b;   /* b を基準とする */
  int tmp2 = test2.b;
  return tmp2 - tmp1;
}

#define MAXSIZE 200000
int list[MAXSIZE];
int tail;

void Init(void){
    tail=0;
}
int Top(void){
    return 0;
}

int Next(int pos){
    if(pos<tail-1){
        return pos+1;
    }else{
        return -1;
    }
}
int Count(void){
    return tail;
}

int Item(int pos){
    if((pos>=0)&&(pos<tail)){
        return list[pos];
    }else{
        return 0;
    }
}
void Add(int value){
    if(tail<MAXSIZE){
        list[tail]=value;
        tail++;
    }
}
void Delete(int pos){
    if((pos>=0)&&(pos<tail)){
        int i;
        for(i=pos;i<tail-1;i++){
            list[i]=list[i+1];
        }
        tail--;
    }
}
int kai(int n){
    if(n==0){
        return 1;
    }
    int sum=1;
    for(int i=1;i<=n;i++){
        sum*=i;
    }
    return sum;
}

int main(){
    char s[27];
    scanf("%s",s);
    rep(i,strlen(s)){
        rep(j,strlen(s)){
            if(j==i){
                ;
            }else if(s[j]==s[i]){
                printf("no");
                return 0;
            }else{
                ;
            }
        }
    }
    printf("yes");
    return 0;
}