#include <stdio.h>

int main(void) {
	int aw, ab, bw, bb, c, d;
	int mw, mb;
	scanf("%d%d", &aw, &ab);
	scanf("%d%d", &bw, &bb);
	scanf("%d%d", &c, &d);
	
	
	if(ab> c){
		mw = 0;
		mb = c;
	}
	else{
		mw = c - ab;
		mb = ab;
	}
	aw = aw - mw;
	ab = ab - mb;
	bw = bw + mw;
	bb = bb + mb;
//	printf("%d %d  %d %d \n", aw, ab, bw, bb);
	if(bw > d){
		mb = 0;
		mw = d;
	}
	else{
		mw = bw;
		mb = d - bw;
	}
	aw = aw + mw;
	ab = ab + mb;
	bw = bw - mw;
	bb = bb - mb;
//	printf("%d %d  %d %d \n", aw, ab, bw, bb);

	printf("%d\n", aw);
	
	return 0;
}