#!/usr/local/gnu/bin/bash
read a b c d
ac=`echo $((c-a)) | tr -d -`
if((ac<=d))
then
    echo Yes
else
    ab=`echo $((b-a)) | tr -d -`
    bc=`echo $((c-b)) | tr -d -`
    if((ab<=d&&bc<=d))
    then
        echo Yes
    else
        echo No
    fi
fi
