#include <stdio.h>
#include <string.h>

int main() {
    char s[1000];
    int i,j;
    scanf("%s", s);
    int n = strlen(s);

    if (n != 0) {
        for ( i = 0; i < n; i++) {
            for ( j = n - 1 - i; j >= 0; j--) {
                if (s[i] != s[j]) {
                    printf("YES");
                    goto end;
                }
                break;
            }
        }
        printf("NO");
    }
   end:
 }
}