'use strict'
let input = require("fs").readFileSync("/dev/stdin", "utf8");
input = input.split('\n').map(x=> x*1);
let ans = "Yay!";
let amount = input.pop();

for(let i = 0; i< input.length; i++){
  for(let j = 0; j< input.length; j++){
    if(i == j){
    	continue
    }
    else if(Math.abs(input[i]-input[j]) >= amount){
      ans = ":(";
      break;
    };
  }
}

console.log(ans);
