AdventOfCodeDay2.cs

var paperNeeded = input.Select(a => new
{
	SurfaceArea = 2 * a.Item1 * a.Item2 + 2 * a.Item1 * a.Item3 + 2 * a.Item2 * a.Item3,
	Extra = Math.Min(Math.Min(a.Item1 * a.Item2, a.Item1 * a.Item3), a.Item2 * a.Item3)
}).Sum(b => b.SurfaceArea + b.Extra);

var ribbonNeeded = input.Select(a => new
{
	Permiter = Math.Min(Math.Min(2 * (a.Item1 + a.Item3), 2 * (a.Item2 + a.Item3)), 2 * (a.Item2 + a.Item1)),
	Extra = a.Item1 * a.Item2 * a.Item3
}).Sum(b => b.Permiter + b.Extra);