#define _USE_MATH_DEFINES	//M_PI(3.14)
#include <iostream>			//std::cout, std::cin
#include <string>			//std::string
#include <vector>			//std::vector
#include <valarray>			//std::valarray	数値のみの一次配列
#include <algorithm>		//std::sort
#include <time.h>			//localtime_s
#include <cstdlib>			//abs
#include <cmath>			//abs, std::pow, sqrt, sin, cos,round,floor
#include <fstream>			//std::ifstream
#include <iomanip>			//std::setprecision
#include <random>			//std::random(C++11)
#include <numeric>			//std::accumulate

int main(void) {

	//test用
	//std::ifstream in("test.txt");
	//std::cin.rdbuf(in.rdbuf());

	//MODULO 10^9+7用
	//const unsigned int M = 1000000007;

	int Aw, Ab, Bw, Bb, C, D;
	std::cin >> Aw >> Ab >> Bw >> Bb >> C >> D;
	int ans = 0;

	if (Bw >= D) {
		ans = Aw + D;
		if (Ab < C) {
			ans -= C - Ab;
		}
	}
	else {
		if (Aw + Bw <= D) {
			ans = Aw + Bw;
		}
		else {
			if (D - Bw >= C) {
				ans = Aw + Bw;
			}
			else {
				if (Ab >= C - (D - Bw)) {
					ans = Aw + Bw;
				}
				else {
					ans = Aw - C + Ab + D;
				}
			}
		}
	}

	std::cout << ans << std::endl;

}