import java.util.Scanner;

class Main {
  public static void main(String[] args) {

    Scanner sc = new Scanner( System.in );
    int A = sc.nextInt();
    int B = sc.nextInt();
    int C = sc.nextInt();

    if ( B > A ) {
      System.out.println("Input Error ( B > A )");
    } else {
      if ( C > (A-B) ) {
        System.out.println(C-(A-B));
      } else {
        System.out.println("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