import 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();
		
		A = A - (B + C);
		
		if(A < 0){
			A = A * -1;
		}
		else if(A > 0){
			A = 0;
		}
		System.out.println(A);
	}
} import java.util.*; util.* java 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();
		
		A = A - (B + C);
		
		if(A < 0){
			A = A * -1;
		}
		else if(A > 0){
			A = 0;
		}
		System.out.println(A);
	}
} 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();
		
		A = A - (B + C);
		
		if(A < 0){
			A = A * -1;
		}
		else if(A > 0){
			A = 0;
		}
		System.out.println(A);
	} main {
		Scanner sc = new Scanner(System.in);
		int A = sc.nextInt();
		int B = sc.nextInt();
		int C = sc.nextInt();
		
		A = A - (B + C);
		
		if(A < 0){
			A = A * -1;
		}
		else if(A > 0){
			A = 0;
		}
		System.out.println(A);
	} 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 A = A - (B + C) A A - (B + C) A (B + C) B C if(A < 0){
			A = A * -1;
		}
		else if(A > 0){
			A = 0;
		} A < 0 A 0 {
			A = A * -1;
		} A = A * -1 A A * -1 A -1 1 if(A > 0){
			A = 0;
		} A > 0 A 0 {
			A = 0;
		} A = 0 A 0 System.out.println(A) System.out.println System.out System System.out A 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();
		
		A = A - (B + C);
		
		if(A < 0){
			A = A * -1;
		}
		else if(A > 0){
			A = 0;
		}
		System.out.println(A);
	}
} 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();
		
		A = A - (B + C);
		
		if(A < 0){
			A = A * -1;
		}
		else if(A > 0){
			A = 0;
		}
		System.out.println(A);
	}
} Main
import 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();
		
		A = A - (B + C);
		
		if(A < 0){
			A = A * -1;
		}
		else if(A > 0){
			A = 0;
		}
		System.out.println(A);
	}
}