import datetime
import sys

sys.setrecursionlimit(10 ** 6)
int1 = lambda x: int(x) - 1
p2D = lambda x: print(*x, sep="\n")
def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]

def main():
    aw,ab=MI()
    bw,bb=MI()
    c,d=MI()
    atob=max(c-ab,0)
    aw,bw=aw-atob,bw+atob
    aw+=min(bw,d)
    print(aw)

main()