tribeau

//#include<bits/stdc++.h>
#include<iostream>
#include<vector>

#define long long long
#define nln '\n'

using namespace std;

// Global variables: a, d

vector<long> a;
long d;

void data()
{
    a.resize(3, 0);
    for (long i = 0; i != 3; ++i)
        cin >> a[i];
    cin >> d;
}

void process()
{
    long max = -1;
    for (long i = 0; i != 2; ++i)
        for (long j = i+1; j != 3; ++j)
        {
            long tem = abs(a[i]-a[j]);
            if (tem > max)
                max = tem;
        }
    if (max > d)
        cout << "No";
    else
        cout << "Yes";
}

int main()
{
    data();
    process();
    return 0;
}