#include <iostream>
#include <vector>
#include <algorithm>
#include <math.h>

#define ALL(x) (x).begin(),(x).end()
#define REP(i,n) for(int i = 0;i < (n);i++)
#define PI 3.14159265359
#define MOD 1000000007

using namespace std;

int main(){
    int ab,aw,bb,bw,c,d;
    cin >> aw >> ab >> bw >> bb >> c >> d;
    if(ab < c){
        aw -= c - ab;
        bw += c - ab;
    }
    if(bw < d)aw += bw;
    else aw += d;
    cout << aw << endl;
    return 0;
}