public static SingleTypeExpression <int, TContext> WithOps <TContext>(this SingleTypeExpression <int, TContext> expr)
{
expr.AddBinary(new BinarySymbol("+", 1), (a, b) => a + b);
expr.AddBinary(new BinarySymbol("-", 1), (a, b) => a - b);
expr.AddBinary(new BinarySymbol("*", 2), (a, b) => a * b);
expr.AddBinary(new BinarySymbol("/", 2), (a, b) => a / b);
expr.AddUnary(new UnarySymbol("-"), i => - i);
return(expr);
}
public override void PartTwo()
{
var expr = new SingleTypeExpression <long>(long.Parse);
expr.AddBinary(new BinarySymbol("+", 2), (a, b) => a + b);
expr.AddBinary(new BinarySymbol("*", 1), (a, b) => a * b);
var sum = Input.Select(expr.Eval).Sum();
WriteLn(sum);
}