import java.util.*;
 
public class Main{
	public static void main(String[] args){
    	Scanner scan = new Scanner(System.in);
      	int a = scan.nextInt();
      	int b = scan.nextInt();
      	int c = scan.nextInt();
      	int rest = a - b;
      	if(c -rest > 0){
        	System.out.print(c - rest);
        }
      	else{
        	System.out.print("0");
        }
    }
}
/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