#include<stdio.h>
#include<ctype.h>
#include<string.h>
int main(){
    char str[1000];
    fgets(str, sizeof(str),stdin);
    int letter[26] = {0};
    int count =0;
    for(int i = 0; str[i] != '\0'; i++){
        if(isalpha(str[i])){
        if index = tolower(str[i]) - 'a';
        if (lrtters[index] ==0){
            letters[index] =1;
            count++;
        }
        }
}
if(count == 26)
printf("YES");
else
print("NO");
return 0;
}