function Main(input) {
  input = input.split("\n");
  var limit = input[input.length -1];
  var max = input[input.length -2] - input[0];
  if(max > limit) {
    console.log(":(")
  } else {
    console.log("Yay!");
  }
}
// Main("0\n1\n2\n3\n4\n3");
Main(require("fs").readFileSync("/dev/stdin", "utf8"));