include <stdio.h>

int main() {

int	a, b, c, d, e, f, g, h, i, j, k, n;
scanf("%d", &a);
b = a % 10;
c = a / 10;
d = c % 10;
e = c / 10;
f = e % 10;
g = e / 10;
h = g % 10;
i = g / 10;
if (b + f == d + h) {
	printf("YES");
} else {
	printf("NO");
}

return 0;

}