import java.util.Scanner;
public class Main {

	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		int Amm = scan.nextInt();
		int Bmm = scan.nextInt();
		int Cmm = scan.nextInt();

		System.out.println(Amm-Bmm >= Cmm?0:Bmm+Cmm-Amm);

		scan.close();

	}

} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		int Amm = scan.nextInt();
		int Bmm = scan.nextInt();
		int Cmm = scan.nextInt();

		System.out.println(Amm-Bmm >= Cmm?0:Bmm+Cmm-Amm);

		scan.close();

	}

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

		Scanner scan = new Scanner(System.in);

		int Amm = scan.nextInt();
		int Bmm = scan.nextInt();
		int Cmm = scan.nextInt();

		System.out.println(Amm-Bmm >= Cmm?0:Bmm+Cmm-Amm);

		scan.close();

	} main {

		Scanner scan = new Scanner(System.in);

		int Amm = scan.nextInt();
		int Bmm = scan.nextInt();
		int Cmm = scan.nextInt();

		System.out.println(Amm-Bmm >= Cmm?0:Bmm+Cmm-Amm);

		scan.close();

	} Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int Amm = scan.nextInt(); Amm scan.nextInt() scan.nextInt scan int Bmm = scan.nextInt(); Bmm scan.nextInt() scan.nextInt scan int Cmm = scan.nextInt(); Cmm scan.nextInt() scan.nextInt scan System.out.println(Amm-Bmm >= Cmm?0:Bmm+Cmm-Amm) System.out.println System.out System System.out Amm-Bmm >= Cmm?0:Bmm+Cmm-Amm Amm-Bmm >= Cmm Amm-Bmm Amm Bmm Cmm 0 Bmm+Cmm-Amm Bmm+Cmm Bmm Cmm Amm scan.close() scan.close scan String[] args args public class Main {

	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		int Amm = scan.nextInt();
		int Bmm = scan.nextInt();
		int Cmm = scan.nextInt();

		System.out.println(Amm-Bmm >= Cmm?0:Bmm+Cmm-Amm);

		scan.close();

	}

} public class Main {

	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		int Amm = scan.nextInt();
		int Bmm = scan.nextInt();
		int Cmm = scan.nextInt();

		System.out.println(Amm-Bmm >= Cmm?0:Bmm+Cmm-Amm);

		scan.close();

	}

} Main
import java.util.Scanner;
public class Main {

	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		int Amm = scan.nextInt();
		int Bmm = scan.nextInt();
		int Cmm = scan.nextInt();

		System.out.println(Amm-Bmm >= Cmm?0:Bmm+Cmm-Amm);

		scan.close();

	}

}
