#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>



int main(int argc, char *argv[])
{

	int Aw = 0;
	int Ab = 0;
	int Bw = 0;
	int Bb = 0;
	int C = 0;
	int D = 0;

	scanf("%d %d", &Aw, &Ab);
	scanf("%d %d", &Bw, &Bb);
	scanf("%d %d", &C, &D);


	if( C >= Ab )
	{
		Bb += Ab;
		Bw += (C - Ab);
		Aw -= (C - Ab);
		Ab = 0;
	}
	else
	{
		Bb += C;
		Ab -= C;
	}

	if (D >= Bw)
	{
		Aw += Bw;
		Ab += (D - Bw);
		Bb -= (D - Bw);
		Bw = 0;
	}
	else
	{
		Aw += D;
		Bw -= D;
	}

	printf("%d\n", Aw);

	return 0;

}