#include<iostream>

using namespace std;

int main()

{

int a,b,c,d;

cin>>a>>b>>c>>d;

int result = b-c;

cout<<result <<endl;

return 0;

}











typedef long long ll;
typedef long double ld;
#include <bits/stdc++.h>
using namespace std;

int main() {
    vector<ll> a(2);
    for (int i = 0; i < 2; i++) {
        std::cin >> a[i];
    }
    sort(a.begin(),a.end());
    
    if(a[0]+3>a[1]){
        std::cout << "Yes" << std::endl;
    }else{
        std::cout << "No" << std::endl;
    }
}
