#include <iostream>
#include <cmath>

using namespace std;

int main()
{
    int a,b,c,d;
    cin >> a >> b >> c >> d;
    if (abs(a-c) <= d || (abs(a-b) <= d && abs(b-c) <= d)) cout << "YES" << endl;
    else cout << "NO" << endl;
    return 0;
}
