import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		// 整数の入力
		int A = sc.nextInt();
		int B = sc.nextInt();
		int C = sc.nextInt();
		int empty = A - B;
		int ret = C- empty;
		if(ret < 0){
			ret = 0;
		}
		System.out.println(ret);

		sc.close();
	}
}

/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