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: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using static System.Console;
using static System.Math;

namespace AtCoder
{
    class Program
    {
        static void Main(string[] args)
        {
            var abc = ReadInts();
            if(abc[1] + abc[2] - abc[0] <= 0)
            {
                WriteLine(0);
            }
            else
            {

            WriteLine(abc[1] + abc[2]-abc[0]);
            }
        }

        private static string Read() { return ReadLine(); }
        private static string[] Reads() { return (Read().Split()); }
        private static int ReadInt() { return int.Parse(Read()); }
        private static long ReadLong() { return long.Parse(Read()); }
        private static double ReadDouble() { return double.Parse(Read()); }
        private static int[] ReadInts() { return Array.ConvertAll(Read().Split(), int.Parse); }
        private static long[] ReadLongs() { return Array.ConvertAll(Read().Split(), long.Parse); }
        private static double[] ReadDoubles() { return Array.ConvertAll(Read().Split(), double.Parse); }

        //最大公約数

        public static int Gcd(int a, int b)
        {
            if (a < b)
            {
                return Gcd(b, a);
            }
            while (b != 0)
            {
                var reminder = a % b;
                a = b;
                b = reminder;
            }
            return a;
        }

        //最小公倍数
        public static int Lcm(int a, int b)
        {
            return a * b / Gcd(a, b);
        }

        //文字数を数える
        public static int CountChar(string s, char c)
        {
            return s.Length - s.Replace(c.ToString(), "").Length;
        }
    }
}