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