#include <iostream>
#include <cstdio>
#include <queue>
#include <cstring>
#include <map>
#include <cmath>
#include <algorithm>
#include <stack>
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;
}
