#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic pop
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;

struct S {
  int il, jl, ir, jr;
  friend ostream& operator<<(ostream& os, const S& r) { return os << "(" << r.il << ", " << r.jl << ", " << r.ir << ", " << r.jr << ")"; }
};

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n1, n2, n3, m;
  cin >> n1 >> n2 >> n3 >> m;
  bool ok = true;
  vector<P> e11, e22, e33, e12, e13, e23;
  rep(_, m) {
    int u, v;
    cin >> u >> v;
    if (u > v) swap(u, v);
    if (v <= n1) {
      e11.emplace_back(u, v);
    } else if (v <= n1 + n2) {
      if (u <= n1) e12.emplace_back(u, v - n1);
      else e22.emplace_back(u - n1, v - n1);
    } else if (v <= n1 + n2 + n3) {
      if (u <= n1) e13.emplace_back(u, v - (n1 + n2));
      else if (u <= n1 + n2) e23.emplace_back(u - n1, v - (n1 + n2));
      else e33.emplace_back(u - (n1 + n2), v - (n1 + n2));
    } else if (v == n1 + n2 + n3 + 1) {
      if (u <= n1) e11.emplace_back(0, u);
      else if (u <= n1 + n2) e22.emplace_back(0, u - n1);
      else e33.emplace_back(0, u - (n1 + n2));
    } else {
      if (u <= n1) e11.emplace_back(u, n1 + 1);
      else if (u <= n1 + n2) e22.emplace_back(u - n1, n2 + 1);
      else if (u <= n1 + n2 + n3) e33.emplace_back(u - (n1 + n2), n3 + 1);
      else ok = false;
    }
  }
  if (!ok) {
    cout << 0 << '\n';
    return 0;
  }
  n1++, n2++, n3++;
  sort(all(e12));
  vector<S> st{{0, 0, -1, -1}};
  for(auto [i, j]: e12) {
    if (i == st.back().il) {
      st.back().jl = j;
    } else if (j <= st.back().jl) {
      S r = st.back(); st.pop_back();
      r.il = i;
      while(!st.empty() && st.back().jl >= j) st.pop_back();
      if (!st.empty()) chmin(st.back().jr, j);
      st.emplace_back(r);
    } else {
      st.back().ir = i;
      st.back().jr = j;
      st.push_back(S{i, j, -1, -1});
    }
  }
  st.back().ir = n1;
  st.back().jr = n2;
  constexpr int INF = 1001001001;
  rep(_, 2) {
    int bad_l = INF, bad_r = -INF;
    for(auto [l, r]: e11) chmin(bad_l, l), chmax(bad_r, r);
    vector<S> nst;
    for(S r: st) {
      if (r.il < bad_l) {
        chmin(r.ir, bad_l);
      } else if (r.ir <= bad_r) {
        continue;
      } else {
        chmax(r.il, bad_r);
      }
      nst.emplace_back(r);
    }
    for(auto& [il, jl, ir, jr]: st) swap(il, jl), swap(ir, jr);
    swap(e11, e22);
  }
  int sz = st.size();
  VL acc(sz + 1);
  rep(i, sz) {
    auto [il, jl, ir, jr] = st[i];
    acc[i+1] = acc[i] + ll(ir - il) * (jr - jl);
  }
  multiset<int, greater<int>> imn{-INF}, jmn{-INF};
  multiset<int> imx{INF}, jmx{INF};
  VVI ev1(n3 + 1), ev2(n3 + 1);
  for(auto [i, k]: e13) {
    imx.insert(i);
    ev1[k].emplace_back(i);
  }
  for(auto [j, k]: e23) {
    jmx.insert(j);
    ev2[k].emplace_back(j);
  }
  int bad_l = INF, bad_r = -INF;
  for(auto [l, r]: e33) chmin(bad_l, l), chmax(bad_r, r);
  auto get_area = [](const S& r1, const S& r2) {
    int il = max(r1.il, r2.il);
    int jl = max(r1.jl, r2.jl);
    int ir = min(r1.ir, r2.ir);
    int jr = min(r1.jr, r2.jr);
    if (il >= ir || jl >= jr) return 0LL;
    return ll(ir - il) * (jr - jl);
  };
  ll ans = 0;
  rep(z, n3) {
    for(int i: ev1[z]) imx.erase(imx.find(i)), imn.insert(i);
    for(int j: ev2[z]) jmx.erase(jmx.find(j)), jmn.insert(j);
    if (bad_l <= z && z < bad_r) continue;
    S r{*imn.begin(), *jmn.begin(), *imx.begin(), *jmx.begin()};
    int from = max(lower_bound(all(st), r, [](const S& x, const S& y) { return x.il < y.il; }) - st.begin(),
                   lower_bound(all(st), r, [](const S& x, const S& y) { return x.jl < y.jl; }) - st.begin());
    int to = min(upper_bound(all(st), r, [](const S& x, const S& y) { return x.ir < y.ir; }) - st.begin(),
                 upper_bound(all(st), r, [](const S& x, const S& y) { return x.jr < y.jr; }) - st.begin());
    if (from < to) ans += acc[to] - acc[from];
    if (from) ans += get_area(st[from - 1], r);
    if (to < sz && to != from - 1) ans += get_area(st[to], r);
  }
  cout << ans << '\n';
}