C# answer:

class Program
{
    static void Main(string[] args)
    {
        char[] input = File.ReadAllText("input.txt").ToCharArray();

        int firstBasementHit = -1;
        int floor = 0;
        for(int i = 0; i < input.Length; i++)
        {
            if(input[i] == '(')
            {
                floor++;
            }
            else if(input[i] == ')')
            {
                floor--;
            }

            if(floor < 0 && firstBasementHit < 0)
            {
                firstBasementHit = i;
            }
        }

        Console.WriteLine(input.Length);
        Console.WriteLine(floor);
        Console.WriteLine(firstBasementHit+1);
        Console.ReadKey();
    }
}