#include <bits/stdc++.h>

using namespace std; 
  
#define     ff              first
#define     ss              second
#define     pb(x)           push_back(x)
#define     mp              make_pair
#define     sz(x)           x.size()
#define     mem(x ,y)       memset(x , y , sizeof x )
#define     all(a )         a.begin() , a.end()
#define     endl            "\n"
#define     pii             pair<int,int> 
#define     clr(x)          x.clear()
#define     rep(i ,n )      for(int i = 0 ; i < n ; i++ )
#define     repi(i ,n )     for(int i = 1 ; i <= n ; i++ )
#define     forn(i ,x,n )   for(int i = x ; i <= n ; i++ )
#define     ford(i ,x,n )   for(int i = x ; i >= n ; i-- )
#define     repit(i, c)     for( __typeof((c).begin()) i = (c).begin(); i != (c).end();++i )
#define     dbg(args...)    do {   cerr << #args << ' ' ;  print(args); } while(0); cerr<< endl ;


#define si(x) scanf("%d",&x)
#define sii(x,y) scanf("%d %d",&x,&y)
#define siii(x,y,z) scanf("%d %d %d",&x,&y,&z)
#define sl(x) scanf("%lld",&x)
#define sll(x,y) scanf("%lld %lld",&x,&y)
#define slll(x,y,z) scanf("%lld %lld %lld",&x,&y,&z)

typedef long long ll  ;
typedef unsigned long long  ull ;
typedef vector<int> vi  ;
 
const int  inf = 0x3f3f3f3f  ;
const ll  mod = 1e9 +7;
const ll  INF = 1e18+1234   ;

int setbit(int n, int pos  ) { return n = n|(1<< pos) ; }
int resetbit(int n,int pos ) {  return n =  n & ~(1<<pos ); }
bool checkbit(int  n,int pos ) { return (bool ) (n&(1<<pos))  ; }
 
template < typename T > T mul(T x, T y   ) { x %= mod ; y %= mod ; return (x*y)%mod  ;  }
template < typename T > T add (T x, T y  ) { x %= mod ; y %= mod ; return (x+y)%mod ;  }
template < typename T > T modPow(T x, T k ,T mod ) { if(k == 0 ) return 1; if(k&1  ) { return ( (x%mod)*modPow(x,k-1, mod )%mod )%mod ; } else { T ret = modPow(x,k/2 , mod ) ; ret %= mod ; return (ret*ret )%mod; } }
template < typename T > T ext_gcd(T num1 , T num2, T &X , T &Y ) { T r2,r1, q2, q1 , x2, x1, y2 ,y1 , x,  y, r   ; x2 = 1; y2 = 0;  x1 = 0; y1 = 1; for( r2 =num1 ,r1 = num2 ;r1 != 0 ; y2 = y1, y1 = y,x2 = x1 ,x1 = x ,r2 = r1, r1 = r) {q1 = r2/r1; x = x2 - q1*x1; y = y2 - q1*y1; r = r2%r1 ; } X = x2 ; Y = y2 ; return r2 ;  }
template < typename T > void print(const T& v) {    cerr << v << ' ' ;}
template < typename T1, typename... T2 > void print( const T1& first, const T2&... rest ){ print(first); print(rest...) ;}
template<class T> string to_str(T t){stringstream ss; ss<<t; return ss.str();} 
template < typename T > 
T  modInv( T x , T m) {  
    return modPow(x,m-2 , m) ;   
    // long long ret, t ;// 
    // ext_gcd( x, m ,ret ,t  ) ;
    // ret %= m ; if(ret<0) ret += m  ; 
    // return ret;
} 
 
// debuging ...
template<typename T > 
void dbg_a(T a[] ,int n=10 ) {
    cerr << "[ "; 
    rep(i,n )
        cerr<<a[i]<<' ' ; 
            cerr<< " ]" <<  endl; 
}
 
template < typename F,  typename S >
ostream& operator << ( ostream& os, const pair< F, S > & p ) {
    return os << "[ " << p.first << ", " << p.second << " ]";
}
 
template < typename T >
ostream &operator << ( ostream & os, const vector< T > &v ) {
    os << "[ "; 
        rep(i , sz( v)  )  
            os << v[i] << ' ' ; 
                return os << " ]\n" ; 
} 

template < typename T >
ostream &operator << ( ostream & os, const map< T ,T> &Map  ) {
    os << "[ "; 
        repit(it , Map )    
            os << "[" <<(*it).ff << ' ' << (*it).ss << "] "    ; 
                return os << "]\n" ; 
} 

template < typename T >
ostream &operator << ( ostream & os, const set< T > &Set  ) {
    os << "[ "; 
        repit(it , Set )   
            os <<  *it  << ' ' ; 
                return os << " ]\n" ; 
} 


//////////////////////////////////////////////////////////////////////////////
// int dx[] = {0 , 0 ,+1, -1 } ;
// int dy[] = {-1, +1,0 , 0 };
// int dx[10 ] =  {-2,-2, 2, 2  ,+ 1, -1  , +1, -1 }  ;
// int dy[10 ] =  {+1,-1, 1, -1 , +2,+2 , -2,-2  }  ;
 
const int M = (int )1e6 +123;  
const int maxn  = (int)2e6 ;
 
////  code from here ...

// // struct tt{

// //     int x, y; 
// //     bool operator<(tt  x )const {
// //         return x<y ; 
// //     }

// } ;
int a , b , c ; 
void solve() { 
      // cerr<< "program running ... " <<  endl ; 
    int n ,x, y , k, q  ,z  , ans = 0 ; 
    // scanf("%d" , &n  ) ;
   
    cin  >> a>> b >> c; 
    a -= b ;
    c -=  a  ; 

   // dbg(a, c ) ; 
    c = max(0,  c)   ; 


    cout << c  <<endl ; 


    // printf("%d" , ans ) ; 
} 


 

// Before submitting check ... 
// Check for ll vs int 
// Check for input 1 .... 
int  main() {
        
    // Comment out freopen .. 
      //freopen("in.txt", "r", stdin);
    //    freopen("out.txt", "w", stdout);
    // ios :: sync_with_stdio(false);  cin.tie(0); cout.tie(0) ;  
 

    int t=1, c =0  ;    
    // scanf("%d",&t) ; 
    while(t--) { 
        // printf("Case %d:" ,++c ) ; 
        
        solve()  ;
     
    }   
    return 0 ;       
} 
// g++ f.cpp -o f.exe 
 














 

Measured memory_bytes: 256