function Main(input){
	input1 = input.split('\n');
    input2 = input1.map(input1=>parseInt(input1,10));
    input3 = input2[0].split(" ");
    a = input2[0];
    b = input2[1];
    c = input2[2];
    d = input2[3];
    if((Math.abs(a-b <=d)) ||(Math.abs(a-b <=d) && Math.abs(b-c <=d))){
    console.log('Yes');
    }else{
    console.log('No');
    }
}
Main(require("fs").readFileSync("/dev/stdin","utf8")