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


int main() {
long long a,b,c,d,e,f;
cin>>a>>b;
cin>>c>>d;
cin>>e>>f;

if(b>e){
}else if(e>b){
	a=a-(e-b);
	c=(e-b)+c;
}

if(f<=c){
	cout<<f+a<<endl;
}else{
	cout<<c+a<<endl;
}

}