import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        int a=scanner.nextInt(),b=scanner.nextInt(),c=scanner.nextInt();

        int diff=a-b;
        if(diff<=c)
            System.out.println(c-diff);
        else
            System.out.println(0);
        
    }
} import java.util.Scanner; Scanner java.util public class Main {

    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        int a=scanner.nextInt(),b=scanner.nextInt(),c=scanner.nextInt();

        int diff=a-b;
        if(diff<=c)
            System.out.println(c-diff);
        else
            System.out.println(0);
        
    }
} Main public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        int a=scanner.nextInt(),b=scanner.nextInt(),c=scanner.nextInt();

        int diff=a-b;
        if(diff<=c)
            System.out.println(c-diff);
        else
            System.out.println(0);
        
    } main {
        Scanner scanner=new Scanner(System.in);
        int a=scanner.nextInt(),b=scanner.nextInt(),c=scanner.nextInt();

        int diff=a-b;
        if(diff<=c)
            System.out.println(c-diff);
        else
            System.out.println(0);
        
    } Scanner scanner=new Scanner(System.in); scanner new Scanner(System.in) int a=scanner.nextInt() a scanner.nextInt() scanner.nextInt scanner b=scanner.nextInt() b scanner.nextInt() scanner.nextInt scanner c=scanner.nextInt(); c scanner.nextInt() scanner.nextInt scanner int diff=a-b; diff a-b a b if(diff<=c)
            System.out.println(c-diff);
        else
            System.out.println(0); diff<=c diff c System.out.println(c-diff) System.out.println System.out System System.out c-diff c diff System.out.println(0) System.out.println System.out System System.out 0 String[] args args public class Main {

    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        int a=scanner.nextInt(),b=scanner.nextInt(),c=scanner.nextInt();

        int diff=a-b;
        if(diff<=c)
            System.out.println(c-diff);
        else
            System.out.println(0);
        
    }
} public class Main {

    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        int a=scanner.nextInt(),b=scanner.nextInt(),c=scanner.nextInt();

        int diff=a-b;
        if(diff<=c)
            System.out.println(c-diff);
        else
            System.out.println(0);
        
    }
} Main
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        int a=scanner.nextInt(),b=scanner.nextInt(),c=scanner.nextInt();

        int diff=a-b;
        if(diff<=c)
            System.out.println(c-diff);
        else
            System.out.println(0);
        
    }
}