import java.util.*;
class Main{
    public static void main(String[] args){
	Scanner stdIn = new Scanner(System.in);
        int A = stdIn.nextInt();
	int B = stdIn.nextInt();
	int C = stdIn.nextInt();
	int o = A-B;
	if(o!=0){
	    C-=o;
	}
	if(C>0){
	    System.out.println(C);
	}else{
	    System.out.println(0);
	}
    }
} import java.util.*; util.* java class Main{
    public static void main(String[] args){
	Scanner stdIn = new Scanner(System.in);
        int A = stdIn.nextInt();
	int B = stdIn.nextInt();
	int C = stdIn.nextInt();
	int o = A-B;
	if(o!=0){
	    C-=o;
	}
	if(C>0){
	    System.out.println(C);
	}else{
	    System.out.println(0);
	}
    }
} Main public static void main(String[] args){
	Scanner stdIn = new Scanner(System.in);
        int A = stdIn.nextInt();
	int B = stdIn.nextInt();
	int C = stdIn.nextInt();
	int o = A-B;
	if(o!=0){
	    C-=o;
	}
	if(C>0){
	    System.out.println(C);
	}else{
	    System.out.println(0);
	}
    } main {
	Scanner stdIn = new Scanner(System.in);
        int A = stdIn.nextInt();
	int B = stdIn.nextInt();
	int C = stdIn.nextInt();
	int o = A-B;
	if(o!=0){
	    C-=o;
	}
	if(C>0){
	    System.out.println(C);
	}else{
	    System.out.println(0);
	}
    } Scanner stdIn = new Scanner(System.in); stdIn new Scanner(System.in) int A = stdIn.nextInt(); A stdIn.nextInt() stdIn.nextInt stdIn int B = stdIn.nextInt(); B stdIn.nextInt() stdIn.nextInt stdIn int C = stdIn.nextInt(); C stdIn.nextInt() stdIn.nextInt stdIn int o = A-B; o A-B A B if(o!=0){
	    C-=o;
	} o!=0 o 0 {
	    C-=o;
	} C-=o C o if(C>0){
	    System.out.println(C);
	}else{
	    System.out.println(0);
	} C>0 C 0 {
	    System.out.println(C);
	} System.out.println(C) System.out.println System.out System System.out C {
	    System.out.println(0);
	} System.out.println(0) System.out.println System.out System System.out 0 String[] args args
import java.util.*;
class Main{
    public static void main(String[] args){
	Scanner stdIn = new Scanner(System.in);
        int A = stdIn.nextInt();
	int B = stdIn.nextInt();
	int C = stdIn.nextInt();
	int o = A-B;
	if(o!=0){
	    C-=o;
	}
	if(C>0){
	    System.out.println(C);
	}else{
	    System.out.println(0);
	}
    }
}
