function Main(input) {

	input = input.split(" ");
	var a = input[0];
	var b = input[1];
	var c = input[2];
	var d = input[3];
	
	if(Math.abs(b - a) <= d && Math.abs(c - b) <= d || Math.abs(a - c) <= d){
		console.log("Yes");
	} else {
		console.log("No");
	}
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));