'use strict'

const main = input => {
	const args = input.split('\n').map(arg => arg.split(' '))
	const a = args.slice(0, 5).map(arg => parseInt(arg[0], 10))
	const k = parseInt(args[5][0], 10)
	let flg = true
	
	for (let i = 0; i < (5 - 1); i++) {
		for (let j = (i + 1); j < 5; j++) {
			if (a[j] - a[i] > k) flg = false
		}
	}

	if (flg) console.log('Yay!')
	else console.log(':(')
}

main(require('fs').readFileSync('/dev/stdin', 'utf8'))
