Problem:
Score : 100 points

Problem Statement

We have two bottles for holding water.

Bottle 1 can hold up to A milliliters of water, and now it contains B milliliters of water.

Bottle 2 contains C milliliters of water.

We will transfer water from Bottle 2 to Bottle 1 as much as possible.

How much amount of water will remain in Bottle 2?

Constraints

All values in input are integers.

1 \leq B \leq A \leq 20

1 \leq C \leq 20

Input

Input is given from Standard Input in the following format:

A B C

Output

Print the integer representing the amount of water, in milliliters, that will remain in Bottle 2.

Sample Input 1

6 4 3

Sample Output 1

1

We will transfer two milliliters of water from Bottle 2 to Bottle 1, and one milliliter of water will remain in Bottle 2.

Sample Input 2

8 3 9

Sample Output 2

4

Sample Input 3

12 3 7

Sample Output 3

0

Solution in C# (Mono 4.6.2.0) (judge verdict: Runtime Error)

using System;

class Program
{
    static void Main(string[] args)
    {
        string s = Console.ReadLine();
        int n = int.Parse(s);

        int len = s.Length;//桁数

        int ret = 0;
        if (len == 1)
        {
            ret = 9;
        }
        else if (len == 2)
        {
            ret = 9;
        }
        else if (len == 3)
        {
            ret = n - 99 + 9;
        }
        else if (len == 4)
        {
            ret = 909;
        }
        else if (len == 5)
        {
            ret = n - 9000 - 90;
        }
        else 
        {
            ret = 90909;
        }



        Console.WriteLine(ret.ToString());

    }
}