function Main(input) {
	input = input.trim().split("\n").map((input)=>Number(input));
  var k = input[5];
  for(var i = 0; i < 5; i++){
    for(var j = i + 1; j < 5; j++){
      if(input[j] - input[i] > k){
         console.log(":(");
        return;
      }
    }
  }
  console.log("Yay!");
  
}

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