public class Main {
	public static void main(String[] args) {
		java.util.Scanner s = new java.util.Scanner(System.in);
		int a = s.nextInt();
		int b = s.nextInt();
		int c = s.nextInt();
		int cap = a - b;
		if(cap>= c) {
			System.out.println(0);
		}else {
			System.out.println(c-cap);
		}
	}
} public class Main {
	public static void main(String[] args) {
		java.util.Scanner s = new java.util.Scanner(System.in);
		int a = s.nextInt();
		int b = s.nextInt();
		int c = s.nextInt();
		int cap = a - b;
		if(cap>= c) {
			System.out.println(0);
		}else {
			System.out.println(c-cap);
		}
	}
} Main public static void main(String[] args) {
		java.util.Scanner s = new java.util.Scanner(System.in);
		int a = s.nextInt();
		int b = s.nextInt();
		int c = s.nextInt();
		int cap = a - b;
		if(cap>= c) {
			System.out.println(0);
		}else {
			System.out.println(c-cap);
		}
	} main {
		java.util.Scanner s = new java.util.Scanner(System.in);
		int a = s.nextInt();
		int b = s.nextInt();
		int c = s.nextInt();
		int cap = a - b;
		if(cap>= c) {
			System.out.println(0);
		}else {
			System.out.println(c-cap);
		}
	} java.util.Scanner s = new java.util.Scanner(System.in); s new java.util.Scanner(System.in) int a = s.nextInt(); a s.nextInt() s.nextInt s int b = s.nextInt(); b s.nextInt() s.nextInt s int c = s.nextInt(); c s.nextInt() s.nextInt s int cap = a - b; cap a - b a b if(cap>= c) {
			System.out.println(0);
		}else {
			System.out.println(c-cap);
		} cap>= c cap c {
			System.out.println(0);
		} System.out.println(0) System.out.println System.out System System.out 0 {
			System.out.println(c-cap);
		} System.out.println(c-cap) System.out.println System.out System System.out c-cap c cap String[] args args public class Main {
	public static void main(String[] args) {
		java.util.Scanner s = new java.util.Scanner(System.in);
		int a = s.nextInt();
		int b = s.nextInt();
		int c = s.nextInt();
		int cap = a - b;
		if(cap>= c) {
			System.out.println(0);
		}else {
			System.out.println(c-cap);
		}
	}
} public class Main {
	public static void main(String[] args) {
		java.util.Scanner s = new java.util.Scanner(System.in);
		int a = s.nextInt();
		int b = s.nextInt();
		int c = s.nextInt();
		int cap = a - b;
		if(cap>= c) {
			System.out.println(0);
		}else {
			System.out.println(c-cap);
		}
	}
} Main
public class Main {
	public static void main(String[] args) {
		java.util.Scanner s = new java.util.Scanner(System.in);
		int a = s.nextInt();
		int b = s.nextInt();
		int c = s.nextInt();
		int cap = a - b;
		if(cap>= c) {
			System.out.println(0);
		}else {
			System.out.println(c-cap);
		}
	}
}
