'use strict'

function main(input) {
  input = input.split('\n')[0].split(' ').map(v => ~~v)
  let d = input.pop()

  if (Math.abs(input[0] - input[1]) <= d && Math.abs(input[1] - input[2]) <= d) console.log('Yes')
  else if (Math.abs(input[0] - input[2]) <= d) console.log('Yes')
  else console.log('No')
}

main(require("fs").readFileSync("/dev/stdin", "utf8"));