#include <stdio.h>
#include <string.h>
#include <ctype.h>
int main() {
    char str[1001];
    int alphapet[26] = {0};
    fgets(str, sizeof(str), stdin);
    for (int i = 0; str[i];  != '\0'; i++) {
        if (isalpha(str[i])) {
            char lower = tolower(str[i]);
            alphapet[lower - 'a'] = 1;
        }
    }
    for (int i = 0; i < 26; i++) {
        if (alphapet[i] == 0) {
            printf("NO\n");
            return 0;
        }
    }
    printf("YES\n");
    return 0;

}