#include <iostream>
#include <cmath>
using namespace std;
 
int main() {
 int X1, Y1, X2, Y2;
 cin >> X1 >> Y1 >> X2 >> Y2;
 if(X1 - 1 == X2 and Y1 + 1 == Y2 || X1 == X2 and Y1 + 1 == Y2 || X1+1 == X2 and Y1 == Y2 || (abs(X1-X2 == 1)) and 
 (abs(Y1-Y2 == 1)) || X1 == X2 and (abs(Y1-Y2 ==1)) || X1 + 1 == X2 and Y1 - 1 == Y2 || X1 + 1 and Y1 == Y2 
 || X1 + 1 == X2 and Y1 + 1 == Y2){
 	cout << "YES";
 }else if(X1 != X2){
 	cout << "NO";
 }
	return 0;
}

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