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();

		while (true) {
			if (A == B || C == 0) {
				System.out.println(C);
				break;
			}
			B++;
			C--;
		}
	}
} 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();

		while (true) {
			if (A == B || C == 0) {
				System.out.println(C);
				break;
			}
			B++;
			C--;
		}
	}
} 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();

		while (true) {
			if (A == B || C == 0) {
				System.out.println(C);
				break;
			}
			B++;
			C--;
		}
	} main {
		Scanner sc = new Scanner(System.in);

		int A = sc.nextInt();
		int B = sc.nextInt();
		int C = sc.nextInt();

		while (true) {
			if (A == B || C == 0) {
				System.out.println(C);
				break;
			}
			B++;
			C--;
		}
	} 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 while (true) {
			if (A == B || C == 0) {
				System.out.println(C);
				break;
			}
			B++;
			C--;
		} true {
			if (A == B || C == 0) {
				System.out.println(C);
				break;
			}
			B++;
			C--;
		} if (A == B || C == 0) {
				System.out.println(C);
				break;
			} A == B || C == 0 A == B A B C == 0 C 0 {
				System.out.println(C);
				break;
			} System.out.println(C) System.out.println System.out System System.out C break; B++ B C-- C 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();

		while (true) {
			if (A == B || C == 0) {
				System.out.println(C);
				break;
			}
			B++;
			C--;
		}
	}
} 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();

		while (true) {
			if (A == B || C == 0) {
				System.out.println(C);
				break;
			}
			B++;
			C--;
		}
	}
} 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();

		while (true) {
			if (A == B || C == 0) {
				System.out.println(C);
				break;
			}
			B++;
			C--;
		}
	}
}