import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

Aw,Ab,Bw,Bb,C,D = map(int,read().split())

b = min(Ab, C)
w = C - b
Aw -= w; Bw += w
Ab -= b; Bb += b

w = min(Bw, D)
b = D - w
Bw -= w; Aw += w
Bb -= b; Ab += b

print(Aw)