import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
    public static void main(String args[]) throws Exception {
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	String strArray[] = br.readLine().split(" ");
	int A, B, C;
	A = Integer.parseInt(strArray[0]);
	B = Integer.parseInt(strArray[1]);
	C = Integer.parseInt(strArray[2]);
	if(B + C > A)
	    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