    #include <iostream>
    #include <cmath>
     
    using namespace std;
     
    int main(){
     
      int a, b, c, d;
     
      cin >> a >> b >> c >> d;
     
        if(abs(a-b) <= d && abs(b-c) <= d) cout << "YES" << endl;
     
        else if(abs(a-c)<=d) cout << "YES" << endl;
     
        else cout << "NO" << endl;
     
     
      return 0;
    }