function Main(input) {
  input = input.split("\n");
  var limit = parseInt(input[input.length -1],10);
  var max = parseInt(input[input.length -2],10) - parseInt(input[0], 10);
  if(max > limit) {
    console.log(":(")
  } else {
    console.log("Yay!");
  }
}

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