function replace(input: string, key: number) : string {
	return input.replace(/([a-z])/g, 
		($1) => String.fromCharCode(($1.charCodeAt(0) + key + 26 - 97) % 26 + 97)
		).replace(/([A-Z])/g, 
		($1) => String.fromCharCode(($1.charCodeAt(0) + key + 26 - 65) % 26 + 65));
}