#include<iostream>
using namespace std;
int main()
{
int n;
cin>>n;
if(n/100+n%10==n/10%10)
cout<<"yes";
}
#include<iostream>
using namespace std;
int main()
{
int n;
cin>>n;
if(n/100+n%10==n/10%10)
cout<<"yes";
}