#include <algorithm>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>

using namespace std;

typedef long long ll;

#define MOD 1000000007

int main() {
  vector<int> v, u;
  int aw, ab;
  cin >> aw >> ab;
  for (int i = 0; i < aw; ++i) {
    v.push_back(0);
  }
  for (int i = 0; i < ab; ++i) {
    v.push_back(1);
  }
  int bw, bb;
  cin >> bw >> bb;
  for (int i = 0; i < bw; ++i) {
    u.push_back(0);
  }
  for (int i = 0; i < bb; ++i) {
    u.push_back(1);
  }
  int c, d;
  cin >> c >> d;
  while (c--) {
    int val = v.back();
    v.pop_back();
    u.push_back(val);
  }
  sort(u.rbegin(), u.rend());
  while (d--) {
    int val = u.back();
    u.pop_back();
    v.push_back(val);
  }
  int ans = 0;
  for (int i = 0; i < v.size(); ++i) {
    ans += (v[i] == 0);
  }
  cout << ans << endl;
  return 0;
}