public override object SolveOne()
{
return(IntRows
.Where(x => IntRows.Contains(2020 - x))
.Select(x => x * (2020 - x))
.First());
}
public override object SolveTwo()
{
return(IntRows
.Where(x => IntRows.Exists(y => IntRows.Contains(2020 - x - y)))
.Aggregate(1, (x, y) => x * y));
}