import strutils, sequtils, math

var
  a_seq = split(readLine(stdin), ' ').mapIt(int, it.parseInt)
  b_seq = split(readLine(stdin), ' ').mapIt(int, it.parseInt)
  cd = split(readLine(stdin), ' ').mapIt(int, it.parseInt)
  tmp_a, tmp_b, result : int

tmp_a = if a_seq[1] < cd[0]: cd[0] - a_seq[1] else: 0
tmp_b = min(cd[1], tmp_a + b_seq[0])
result = (a_seq[0] - tmp_a) + tmp_b

echo(result)