import bisect
import copy
import decimal
import fractions
import heapq
import itertools
import math
import random
import sys
import time
from collections import Counter,deque,defaultdict
from functools import lru_cache,reduce
from heapq import heappush,heappop,heapify,heappushpop,_heappop_max,_heapify_max
def _heappush_max(heap,item):
    heap.append(item)
    heapq._siftdown_max(heap, 0, len(heap)-1)
def _heappushpop_max(heap, item):
    if heap and item < heap[0]:
        item, heap[0] = heap[0], item
        heapq._siftup_max(heap, 0)
    return item
from math import gcd as GCD
read=sys.stdin.read
readline=sys.stdin.readline
readlines=sys.stdin.readlines
write=sys.stdout.write

A=list(map(int,readline().split()))
B=list(map(int,readline().split()))
C,D=map(int,readline().split())
w=min(C,A[1])
C-=w
A[1]-=w
B[1]+=w
A[0]-=C
B[0]+=C
b=min(D,B[0])
D-=b
B[0]-=b
A[0]+=b
B[1]-=D
A[1]+=D
ans=A[0]
print(ans)