function Main(input){
	input1 = input.split('\n');
    input2 = input1.map(input1=>parseInt(input1,10));
    a = input3[0];
    b = input3[1];
    c = input3[2];
    d = input3[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"));