include

using namespace std; int main(){

int num;
cin >> num;
int q, b, s, g;
q = num/1000;
num = num - q*1000;
b = num/100;
num = num - b*100;
s = num/10;
num = num - s*10;
g = num/1;
if(q + s == b + g) cout << "YES";
else cout << "NO";

}