#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

int main ()
{
    int size = 0;
    int *a = (int*)malloc(size*sizeof(int));
    int j;
    bool tstr = 1;
    char c;
    while(c != '\n'){
        a = (int*)realloc(a, (size+1)*sizeof(int));
        scanf("%d%c", &a[size++], &c);
    }
    for(int i =0, j = size -1; i<j && tstr; i++, j--)
        tstr = (a[i] == a[j]);
    printf("%s\n", tstr? "yes": "no");
    free(a);
    return 0;
}