#include<stdio.h>
int main()
{
    char s[50],ans[100];
    int i,count=0;
    scanf("%s",s);
    sprintf(ans,"%s%s",s,s);
    for(i=0;;i++){
        if(s[i]==ans[i]){
            count=1;
        }else{
            count=0;
            break;
        }
    }
    switch(count){
        case 1:
        printf("YES\n");
        break;
        case 0:
        printf("NO\n");
        break;
    }
    return 0;
}