import java.util.*;
import java.util.Map.Entry;
import java.io.*;
import java.lang.reflect.Array;
import java.math.BigInteger;
import java.rmi.server.UnicastRemoteObject;

import static java.lang.Math.*;
import static java.util.Arrays.*;
import static java.util.Collections.*;
 
public class Main{
    static long mod=1000000007;
//    static int dx[]={-1,0,1,0};
//    static int dy[]={0,-1,0,1};

    public static void main(String[] args)   throws Exception, IOException{        
        Reader sc = new Reader(System.in);
        PrintWriter out=new PrintWriter(System.out);
        
        int r=sc.nextInt()-sc.nextInt();
        int c=sc.nextInt();

        
      
        out.println(max(0,c-r));
        out.flush();
    }



    static boolean validpos(int x,int y,int r, int c){
        return x<r && 0<=x && y<c && 0<=y;
    }

    static void db(Object... os){
        System.err.println(Arrays.deepToString(os));
    }
}

class P {
	int x, y;
	P(int  x, int y) {
	  this.x=x;
	  this.y=y;
	}
}


//class P {
//    int id, d;
//    P(int  id, int d) {
//        this.id=id;
//        this.d=d;
//    }
//}

//class P implements Comparable<P>{
//    int a,b;
//    P(int a, int b) {
//    	this.b=b;
//    	this.a=a;
//    }
//
//    public int compareTo(P p){
//        return b-p.b;
//    }
//}

class Reader
{ 
    private BufferedReader x;
    private StringTokenizer st;
    
    public Reader(InputStream in)
    {
        x = new BufferedReader(new InputStreamReader(in));
        st = null;
    }
    public String nextString() throws IOException
    {
        while( st==null || !st.hasMoreTokens() )
            st = new StringTokenizer(x.readLine());
        return st.nextToken();
    }
    public int nextInt() throws IOException
    {
        return Integer.parseInt(nextString());
    }
    public int[] nextIntArray(int size) throws IOException{
        int r[] = new int[size];
        for (int i = 0; i < size; i++) {
            r[i] = this.nextInt(); 
        }
        return r;
    }
    public long[] nextLongArray(int size) throws IOException{
        long r[] = new long[size];
        for (int i = 0; i < size; i++) {
            r[i] = this.nextLong(); 
        }
        return r;
    }
    public long nextLong() throws IOException
    {
        return Long.parseLong(nextString());
    }
    public double nextDouble() throws IOException
    {
        return Double.parseDouble(nextString());
    }
} import java.util.*; util.* java import java.util.Map.Entry; Entry java.util.Map import java.io.*; io.* java import java.lang.reflect.Array; Array java.lang.reflect import java.math.BigInteger; BigInteger java.math import java.rmi.server.UnicastRemoteObject; UnicastRemoteObject java.rmi.server import static java.lang.Math.*; import static java.lang.Math.*; import static java.lang.Math.*; import static java.util.Arrays.*; import static java.util.Arrays.*; import static java.util.Arrays.*; import static java.util.Collections.*; import static java.util.Collections.*; import static java.util.Collections.*; public class Main{
    static long mod=1000000007;
//    static int dx[]={-1,0,1,0};
//    static int dy[]={0,-1,0,1};

    public static void main(String[] args)   throws Exception, IOException{        
        Reader sc = new Reader(System.in);
        PrintWriter out=new PrintWriter(System.out);
        
        int r=sc.nextInt()-sc.nextInt();
        int c=sc.nextInt();

        
      
        out.println(max(0,c-r));
        out.flush();
    }



    static boolean validpos(int x,int y,int r, int c){
        return x<r && 0<=x && y<c && 0<=y;
    }

    static void db(Object... os){
        System.err.println(Arrays.deepToString(os));
    }
} Main static long mod=1000000007; mod 1000000007 public static void main(String[] args)   throws Exception, IOException{        
        Reader sc = new Reader(System.in);
        PrintWriter out=new PrintWriter(System.out);
        
        int r=sc.nextInt()-sc.nextInt();
        int c=sc.nextInt();

        
      
        out.println(max(0,c-r));
        out.flush();
    } main {        
        Reader sc = new Reader(System.in);
        PrintWriter out=new PrintWriter(System.out);
        
        int r=sc.nextInt()-sc.nextInt();
        int c=sc.nextInt();

        
      
        out.println(max(0,c-r));
        out.flush();
    } Reader sc = new Reader(System.in); sc new Reader(System.in) PrintWriter out=new PrintWriter(System.out); out new PrintWriter(System.out) int r=sc.nextInt()-sc.nextInt(); r sc.nextInt()-sc.nextInt() sc.nextInt() sc.nextInt sc sc.nextInt() sc.nextInt sc int c=sc.nextInt(); c sc.nextInt() sc.nextInt sc out.println(max(0,c-r)) out.println out max(0,c-r) max 0 c-r c r out.flush() out.flush out String[] args args static boolean validpos(int x,int y,int r, int c){
        return x<r && 0<=x && y<c && 0<=y;
    } validpos {
        return x<r && 0<=x && y<c && 0<=y;
    } return x<r && 0<=x && y<c && 0<=y; x<r && 0<=x && y<c && 0<=y y<c x<r && 0<=x && y<c && 0<=y x<r x r 0<=x 0 x y<c y c 0<=y 0 y int x x int y y int r r int c c static void db(Object... os){
        System.err.println(Arrays.deepToString(os));
    } db {
        System.err.println(Arrays.deepToString(os));
    } System.err.println(Arrays.deepToString(os)) System.err.println System.err System System.err Arrays.deepToString(os) Arrays.deepToString Arrays os Object... os os class P {
	int x, y;
	P(int  x, int y) {
	  this.x=x;
	  this.y=y;
	}
} P int x x y; y P(int  x, int y) {
	  this.x=x;
	  this.y=y;
	} P {
	  this.x=x;
	  this.y=y;
	} this.x=x this.x this this.x x this.y=y this.y this this.y y int  x x int y y class Reader
{ 
    private BufferedReader x;
    private StringTokenizer st;
    
    public Reader(InputStream in)
    {
        x = new BufferedReader(new InputStreamReader(in));
        st = null;
    }
    public String nextString() throws IOException
    {
        while( st==null || !st.hasMoreTokens() )
            st = new StringTokenizer(x.readLine());
        return st.nextToken();
    }
    public int nextInt() throws IOException
    {
        return Integer.parseInt(nextString());
    }
    public int[] nextIntArray(int size) throws IOException{
        int r[] = new int[size];
        for (int i = 0; i < size; i++) {
            r[i] = this.nextInt(); 
        }
        return r;
    }
    public long[] nextLongArray(int size) throws IOException{
        long r[] = new long[size];
        for (int i = 0; i < size; i++) {
            r[i] = this.nextLong(); 
        }
        return r;
    }
    public long nextLong() throws IOException
    {
        return Long.parseLong(nextString());
    }
    public double nextDouble() throws IOException
    {
        return Double.parseDouble(nextString());
    }
} Reader private BufferedReader x; x private StringTokenizer st; st public Reader(InputStream in)
    {
        x = new BufferedReader(new InputStreamReader(in));
        st = null;
    } Reader {
        x = new BufferedReader(new InputStreamReader(in));
        st = null;
    } x = new BufferedReader(new InputStreamReader(in)) x new BufferedReader(new InputStreamReader(in)) st = null st null InputStream in in public String nextString() throws IOException
    {
        while( st==null || !st.hasMoreTokens() )
            st = new StringTokenizer(x.readLine());
        return st.nextToken();
    } nextString {
        while( st==null || !st.hasMoreTokens() )
            st = new StringTokenizer(x.readLine());
        return st.nextToken();
    } while( st==null || !st.hasMoreTokens() )
            st = new StringTokenizer(x.readLine()); st==null || !st.hasMoreTokens() st==null st null !st.hasMoreTokens() st.hasMoreTokens() st.hasMoreTokens st st = new StringTokenizer(x.readLine()) st new StringTokenizer(x.readLine()) return st.nextToken(); st.nextToken() st.nextToken st public int nextInt() throws IOException
    {
        return Integer.parseInt(nextString());
    } nextInt {
        return Integer.parseInt(nextString());
    } return Integer.parseInt(nextString()); Integer.parseInt(nextString()) Integer.parseInt Integer nextString() nextString public int[] nextIntArray(int size) throws IOException{
        int r[] = new int[size];
        for (int i = 0; i < size; i++) {
            r[i] = this.nextInt(); 
        }
        return r;
    } nextIntArray {
        int r[] = new int[size];
        for (int i = 0; i < size; i++) {
            r[i] = this.nextInt(); 
        }
        return r;
    } int r[] = new int[size]; r new int[size] size for (int i = 0; i < size; i++) {
            r[i] = this.nextInt(); 
        } int i = 0; int i = 0; i 0 i < size i size i++ i++ i {
            r[i] = this.nextInt(); 
        } {
            r[i] = this.nextInt(); 
        } r[i] = this.nextInt() r[i] r i this.nextInt() this.nextInt this return r; r int size size public long[] nextLongArray(int size) throws IOException{
        long r[] = new long[size];
        for (int i = 0; i < size; i++) {
            r[i] = this.nextLong(); 
        }
        return r;
    } nextLongArray {
        long r[] = new long[size];
        for (int i = 0; i < size; i++) {
            r[i] = this.nextLong(); 
        }
        return r;
    } long r[] = new long[size]; r new long[size] size for (int i = 0; i < size; i++) {
            r[i] = this.nextLong(); 
        } int i = 0; int i = 0; i 0 i < size i size i++ i++ i {
            r[i] = this.nextLong(); 
        } {
            r[i] = this.nextLong(); 
        } r[i] = this.nextLong() r[i] r i this.nextLong() this.nextLong this return r; r int size size public long nextLong() throws IOException
    {
        return Long.parseLong(nextString());
    } nextLong {
        return Long.parseLong(nextString());
    } return Long.parseLong(nextString()); Long.parseLong(nextString()) Long.parseLong Long nextString() nextString public double nextDouble() throws IOException
    {
        return Double.parseDouble(nextString());
    } nextDouble {
        return Double.parseDouble(nextString());
    } return Double.parseDouble(nextString()); Double.parseDouble(nextString()) Double.parseDouble Double nextString() nextString public class Main{
    static long mod=1000000007;
//    static int dx[]={-1,0,1,0};
//    static int dy[]={0,-1,0,1};

    public static void main(String[] args)   throws Exception, IOException{        
        Reader sc = new Reader(System.in);
        PrintWriter out=new PrintWriter(System.out);
        
        int r=sc.nextInt()-sc.nextInt();
        int c=sc.nextInt();

        
      
        out.println(max(0,c-r));
        out.flush();
    }



    static boolean validpos(int x,int y,int r, int c){
        return x<r && 0<=x && y<c && 0<=y;
    }

    static void db(Object... os){
        System.err.println(Arrays.deepToString(os));
    }
} public class Main{
    static long mod=1000000007;
//    static int dx[]={-1,0,1,0};
//    static int dy[]={0,-1,0,1};

    public static void main(String[] args)   throws Exception, IOException{        
        Reader sc = new Reader(System.in);
        PrintWriter out=new PrintWriter(System.out);
        
        int r=sc.nextInt()-sc.nextInt();
        int c=sc.nextInt();

        
      
        out.println(max(0,c-r));
        out.flush();
    }



    static boolean validpos(int x,int y,int r, int c){
        return x<r && 0<=x && y<c && 0<=y;
    }

    static void db(Object... os){
        System.err.println(Arrays.deepToString(os));
    }
} Main
import java.util.*;
import java.util.Map.Entry;
import java.io.*;
import java.lang.reflect.Array;
import java.math.BigInteger;
import java.rmi.server.UnicastRemoteObject;

import static java.lang.Math.*;
import static java.util.Arrays.*;
import static java.util.Collections.*;
 
public class Main{
    static long mod=1000000007;
//    static int dx[]={-1,0,1,0};
//    static int dy[]={0,-1,0,1};

    public static void main(String[] args)   throws Exception, IOException{        
        Reader sc = new Reader(System.in);
        PrintWriter out=new PrintWriter(System.out);
        
        int r=sc.nextInt()-sc.nextInt();
        int c=sc.nextInt();

        
      
        out.println(max(0,c-r));
        out.flush();
    }



    static boolean validpos(int x,int y,int r, int c){
        return x<r && 0<=x && y<c && 0<=y;
    }

    static void db(Object... os){
        System.err.println(Arrays.deepToString(os));
    }
}

class P {
	int x, y;
	P(int  x, int y) {
	  this.x=x;
	  this.y=y;
	}
}


//class P {
//    int id, d;
//    P(int  id, int d) {
//        this.id=id;
//        this.d=d;
//    }
//}

//class P implements Comparable<P>{
//    int a,b;
//    P(int a, int b) {
//    	this.b=b;
//    	this.a=a;
//    }
//
//    public int compareTo(P p){
//        return b-p.b;
//    }
//}

class Reader
{ 
    private BufferedReader x;
    private StringTokenizer st;
    
    public Reader(InputStream in)
    {
        x = new BufferedReader(new InputStreamReader(in));
        st = null;
    }
    public String nextString() throws IOException
    {
        while( st==null || !st.hasMoreTokens() )
            st = new StringTokenizer(x.readLine());
        return st.nextToken();
    }
    public int nextInt() throws IOException
    {
        return Integer.parseInt(nextString());
    }
    public int[] nextIntArray(int size) throws IOException{
        int r[] = new int[size];
        for (int i = 0; i < size; i++) {
            r[i] = this.nextInt(); 
        }
        return r;
    }
    public long[] nextLongArray(int size) throws IOException{
        long r[] = new long[size];
        for (int i = 0; i < size; i++) {
            r[i] = this.nextLong(); 
        }
        return r;
    }
    public long nextLong() throws IOException
    {
        return Long.parseLong(nextString());
    }
    public double nextDouble() throws IOException
    {
        return Double.parseDouble(nextString());
    }
}
