# 入力の読み込み
A_w, A_b = map(int, input().split())
B_w, B_b = map(int, input().split())
C, D = map(int, input().split())

# 取り得る白石の数の最小値と最大値を計算
x_min = max(0, C - A_b)
x_max = min(C, A_w)

# 各ケースを判定
case1 = (B_w + x_max) <= D
case2 = (B_w + x_min) >= D

if case1:
    max_white = A_w + B_w
elif case2:
    max_white = (A_w - x_min) + D
else:
    max_white = A_w + B_w

print(max_white)