#include <bits/stdc++.h>
using namespace std;

#define M1 1000000007
#define M2 998244353
#define INF 1e18
#define ll long long
#define pll pair<ll,ll>
#define REP(i,a,b) for(ll i=a;i<b;i++)
#define REPR(i,a,b) for(ll i=b-1;i>=a;i--)
#define forr(i,n) for(ll i=0;i<n;i++)
#define F first
#define S second
#define pb push_back
#define DB pop_back
#define mp make_pair
#define MT make_tuple
#define V(a) vector<a>
#define vi vector<int>
#define vlli vector <long long>
#define endl '\n'
#define ce(ele) cout<<ele<<' '
#define cs(ele) cout<<ele<<'\n'
#define CASE(t) ll t; cin>>t; while(t--)

/********************************************************************/
const double pi = 3.1415926535;
/********************************************************************/
//FAST IO//
void FAST() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
}

/********************************************************************/
int main()
{
  FAST();
  int a,b,c,d; cin>>a>>b>>c>>d;
  cout<<b-c<<endl;
  
}
#include <bits/stdc++.h>
#include<sstream>
#include<string>
#include<vector>
#include <set>
#define IOS ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define pb push_back
#define mp make_pair
#define ll long long
#define ff first
#define ss second
long long M=1000000007;
using namespace std;
ll fact[10000];
ll power(ll x, unsigned ll y, unsigned ll m) 
{ 
    if (y == 0) 
        return 1; 
    ll p = power(x, y / 2, m) % m; 
    p = (p * p) % m; 
  
    return (y % 2 == 0) ? p : (x * p) % m; 
} 
unsigned long long modInverse(unsigned long long n,  
                                            int p)
{
    return power(n, p - 2, p);
}
unsigned long long nCrModPFermat(unsigned long long n,
                                 int r, int p)
{
    // If n<r, then nCr should return 0
    if (n < r)
        return 0;
    // Base case
    if (r == 0)
        return 1;
    return (fact[n] * modInverse(fact[r], p) % p
            * modInverse(fact[n - r], p) % p)
           % p;
}
int32_t main()
{
  IOS
  ll a,b,c,d;
  cin>>a>>b>>c>>d;
  cout<<(b-(c))<<endl;
  return 0;
}
