import java.util.* ;
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 x = a-b;
    if(c<=x){
      System.out.println(0);
    }else{
      int y = Math.abs(c-x);
      System.out.println(y);
    }
    
    
    
  }
}


/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