function main(input) {
	input = input.split("\n");
	const d = parseInt(input.shift());
	const s1 = Math.floor(d / 4);
	const s2 = Math.floor((d - s1 * 2) / 2);
	console.log(s1 * s2);
}

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