import java.util.*;

public class Main
{
	public static void main(String args[])
	{
		Scanner sc=new Scanner(System.in);
		int a,b,c;
		a=sc.nextInt();
		b=sc.nextInt();
		c=sc.nextInt();
		if(a>b+c)
		{
			System.out.println("0");
		}
		else
		{
			System.out.println(Math.abs(b+c-a));
		}
	}
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz