#include <stdio.h>
int main() {
char ch;
scanf("%c",&ch);
if(('a'<=ch&&'z'>=ch)||('A'<=ch&&'Z'>=ch)){
printf("YES");
}
else{
printf("NO");
}
return 0;
}

#include <stdio.h>
int main() {
char ch;
scanf("%c",&ch);
if(('a'<=ch&&'z'>=ch)||('A'<=ch&&'Z'>=ch)){
printf("YES");
}
else{
printf("NO");
}
return 0;
}