#include<stdio.h>
int main()
{
char A;
while((A=getchar())!=EOF)
{
getchar();
if(A>='A'&&A<='Z')
{
printf("YES\n");
}
else if(A>='a'&&A<='z')
{
printf("YES\n");
}
else
{
printf("NO\n");
}
}
return 0;
}