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

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