#include <iostream>

using namespace std;
long long a1,a2,a3,a4,s1,s2;
int main()
{
    cin>>a1>>a2>>a3>>a4;
    s1==a1+a2;
    s2==a3+a4;
    if(s1%2==s2%2 )cout<<"YES"<<endl;
    else cout<<"NO"<<endl;
    return 0;
}