#include <iostream>
#include <cstdlib>
using namespace std;

int main()
{
    long long  x1,x2,y1,y2;
    cin>>x1>>y1>>x2>>y2;
    if(abs(x1-x2) == 2 && abs(y1-y2) == 1)
        cout << "Yes\n";
    else if(abs(y1-y2) == 2 && abs(x1-x2) == 1)
        cout << "Yes\n";
    else
        cout << "No\n";
    return 0;
}