#include <stdio.h>

int main(void){
	int a[2], b[2];
	int c,d;
	int white, black;
	
	scanf("%d %d", &white,&black);
	a[0] = white;
	a[1] = black;
	scanf("%d %d", &white,&black);
	b[0] = white;
	b[1] = black;
	
	scanf("%d %d", &c,&d);
	
	if( c >= a[1] ){
		b[1] += a[1];
		c = c - a[1];
		a[1] = 0;
	}else{
		b[1] += c;
		a[1] -= c;
		c = 0;
	}
	
	b[0] += c;
	a[0] -= c;
	
	if( d >= b[0] ){
		a[0] += b[0];
	}else{
		a[0] += d;
	}
	
	printf("%d\n", a[0]);
	return 0;
}