import java.util.Scanner;

public 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((A-B) >= C) {
			System.out.print(0);
		} else if ((A-B) < C ) {
			System.out.print(C-(A-B));
		}
	}
} import java.util.Scanner; Scanner java.util public 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((A-B) >= C) {
			System.out.print(0);
		} else if ((A-B) < C ) {
			System.out.print(C-(A-B));
		}
	}
} 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((A-B) >= C) {
			System.out.print(0);
		} else if ((A-B) < C ) {
			System.out.print(C-(A-B));
		}
	} main {

		Scanner sc = new Scanner(System.in);

		int A = sc.nextInt();
		int B = sc.nextInt();
		int C = sc.nextInt();
		
		if((A-B) >= C) {
			System.out.print(0);
		} else if ((A-B) < C ) {
			System.out.print(C-(A-B));
		}
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int A = sc.nextInt(); A sc.nextInt() sc.nextInt sc int B = sc.nextInt(); B sc.nextInt() sc.nextInt sc int C = sc.nextInt(); C sc.nextInt() sc.nextInt sc if((A-B) >= C) {
			System.out.print(0);
		} else if ((A-B) < C ) {
			System.out.print(C-(A-B));
		} (A-B) >= C (A-B) A B C {
			System.out.print(0);
		} System.out.print(0) System.out.print System.out System System.out 0 if ((A-B) < C ) {
			System.out.print(C-(A-B));
		} (A-B) < C (A-B) A B C {
			System.out.print(C-(A-B));
		} System.out.print(C-(A-B)) System.out.print System.out System System.out C-(A-B) C (A-B) A B String[] args args public 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((A-B) >= C) {
			System.out.print(0);
		} else if ((A-B) < C ) {
			System.out.print(C-(A-B));
		}
	}
} public 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((A-B) >= C) {
			System.out.print(0);
		} else if ((A-B) < C ) {
			System.out.print(C-(A-B));
		}
	}
} Main
import java.util.Scanner;

public 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((A-B) >= C) {
			System.out.print(0);
		} else if ((A-B) < C ) {
			System.out.print(C-(A-B));
		}
	}
}