import std.algorithm, std.array, std.container, std.range;
import std.numeric, std.math, std.bigint, std.bitmanip, std.random;
import std.string, std.conv, std.stdio, std.typecons;

void main()
{
  auto rd1 = readln.split.map!(to!int);
  auto aw = rd1[0], ab = rd1[1];
  auto rd2 = readln.split.map!(to!int);
  auto bw = rd2[0], bb = rd2[1];
  auto rd3 = readln.split.map!(to!int);
  auto c = rd3[0], d = rd3[1];

  auto b1 = min(ab, c);
  aw -= c - b1;
  bw += c - b1;
  auto w2 = min(bw, d);
  aw += w2;

  writeln(aw);
}