"use strict";
    
const main = arg => {
    arg = arg.split("\n");
    
    const k = arg[arg.length - 1];
    
    const antennas = arg.slice(0, 5).map(n=>~~n);
    
    console.log(antennas[4] - antennas[0] > k ? ":(" : "Yay!");
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));
