# -*- coding: utf-8 -*-

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

# Aに残ってる最大の白
W = Aw + min(0, Ab - C)
# Bに移動する白分追加
Bw += -min(0, Ab - C)

print W + min(D, Bw)