#include<stdio.h>

int main(void) {
	int Aw, Ab, Bw, Bb, C, D;
	scanf("%d %d %d %d %d %d", &Aw, &Ab, &Bw, &Bb, &C, &D);

	if (C - Ab > 0) {
		Aw -= (C - Ab);
		Bw += (C - Ab);
	}
	if (D - Bw < 0) {
		Aw += D;
	}else {
		Aw += Bw;
	}
	printf("%d", Aw);
}